21785464801 has 9 divisors (see below), whose sum is σ = 22014390099. Its totient is φ = 21558900336.

The previous prime is 21785464739. The next prime is 21785464819. The reversal of 21785464801 is 10846458712.

The square root of 21785464801 is 147599.

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

It can be written as a sum of positive squares in only one way, i.e., 18067392225 + 3718072576 = 134415^2 + 60976^2 .

It is not a de Polignac number, because 21785464801 - 2⁹ = 21785464289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21785464601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 15201981 + ... + 15203413.

Almost surely, 2^21785464801 is an apocalyptic number.

21785464801 is the 147599-th square number.

21785464801 is the 73800-th centered octagonal number.

It is an amenable number.

21785464801 is a deficient number, since it is larger than the sum of its proper divisors (228925298).

21785464801 is an frugal number, since it uses more digits than its factorization.

21785464801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3072 (or 1536 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 46.

The spelling of 21785464801 in words is "twenty-one billion, seven hundred eighty-five million, four hundred sixty-four thousand, eight hundred one".