399020885761 has 3 divisors (see below), whose sum is σ = 399021517443. Its totient is φ = 399020254080.

The previous prime is 399020885741. The next prime is 399020885773. The reversal of 399020885761 is 167588020993.

The square root of 399020885761 is 631681.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 154945364161 + 244075521600 = 393631^2 + 494040^2 .

It is not a de Polignac number, because 399020885761 - 2⁵ = 399020885729 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399020885696 and 399020885705.

It is not an unprimeable number, because it can be changed into a prime (399020885741) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 315841 + ... + 947521.

It is an arithmetic number, because the mean of its divisors is an integer number (133007172481).

Almost surely, 2^399020885761 is an apocalyptic number.

399020885761 is the 631681-st square number.

399020885761 is the 315841-st centered octagonal number.

It is an amenable number.

399020885761 is a deficient number, since it is larger than the sum of its proper divisors (631682).

399020885761 is an frugal number, since it uses more digits than its factorization.

399020885761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1263362 (or 631681 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 58.

The spelling of 399020885761 in words is "three hundred ninety-nine billion, twenty million, eight hundred eighty-five thousand, seven hundred sixty-one".