21652780925 has 12 divisors (see below), whose sum is σ = 26875777236. Its totient is φ = 17305238400.

The previous prime is 21652780921. The next prime is 21652780937. The reversal of 21652780925 is 52908725612.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 2261382916 + 19391398009 = 47554^2 + 139253^2 .

It is not a de Polignac number, because 21652780925 - 2² = 21652780921 is a prime.

It is a hoax number, since the sum of its digits (47) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21652780925.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21652780921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 398624 + ... + 449673.

It is an arithmetic number, because the mean of its divisors is an integer number (2239648103).

Almost surely, 2^21652780925 is an apocalyptic number.

21652780925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21652780925 is a deficient number, since it is larger than the sum of its proper divisors (5222996311).

21652780925 is a wasteful number, since it uses less digits than its factorization.

21652780925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849328 (or 849323 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 47.

The spelling of 21652780925 in words is "twenty-one billion, six hundred fifty-two million, seven hundred eighty thousand, nine hundred twenty-five".