209381739260841 has 63 divisors (see below), whose sum is σ = 365187484194183. Its totient is φ = 119645145385920.

The previous prime is 209381739260839. The next prime is 209381739260857. The reversal of 209381739260841 is 148062937183902.

The square root of 209381739260841 is 14470029.

It is a perfect power (a square), and thus also a powerful number.

209381739260841 is a `hidden beast` number, since 2 + 0 + 9 + 3 + 8 + 17 + 3 + 9 + 2 + 608 + 4 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 106143134051241 + 103238605209600 = 10302579^2 + 10160640^2 .

It is a tau number, because it is divible by the number of its divisors (63).

It is not a de Polignac number, because 209381739260841 - 2¹ = 209381739260839 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (209381739260831) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 2734797201 + ... + 2734873761.

It is an arithmetic number, because the mean of its divisors is an integer number (5796626733241).

Almost surely, 2^{209381739260841} is an apocalyptic number.

209381739260841 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

209381739260841 is the 14470029-th square number.

209381739260841 is the 7235015-th centered octagonal number.

It is an amenable number.

209381739260841 is a deficient number, since it is larger than the sum of its proper divisors (155805744933342).

209381739260841 is an frugal number, since it uses more digits than its factorization.

209381739260841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153154 (or 76571 counting only the distinct ones).

The product of its (nonzero) digits is 31352832, while the sum is 63.

The spelling of 209381739260841 in words is "two hundred nine trillion, three hundred eighty-one billion, seven hundred thirty-nine million, two hundred sixty thousand, eight hundred forty-one".