21506896525 has 6 divisors (see below), whose sum is σ = 26668551722. Its totient is φ = 17205517200.

The previous prime is 21506896517. The next prime is 21506896601. The reversal of 21506896525 is 52569860512.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 2136380841 + 19370515684 = 46221^2 + 139178^2 .

It is not a de Polignac number, because 21506896525 - 2³ = 21506896517 is a prime.

It is a super-3 number, since 3×21506896525³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 430137906 + ... + 430137955.

Almost surely, 2^21506896525 is an apocalyptic number.

21506896525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21506896525 is a deficient number, since it is larger than the sum of its proper divisors (5161655197).

21506896525 is an equidigital number, since it uses as much as digits as its factorization.

21506896525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 860275871 (or 860275866 counting only the distinct ones).

The product of its (nonzero) digits is 1296000, while the sum is 49.

The spelling of 21506896525 in words is "twenty-one billion, five hundred six million, eight hundred ninety-six thousand, five hundred twenty-five".