21502647025 has 12 divisors (see below), whose sum is σ = 27523389184. Its totient is φ = 16647210000.

The previous prime is 21502647011. The next prime is 21502647043. The reversal of 21502647025 is 52074620512.

It is a de Polignac number, because none of the positive numbers 2^k-21502647025 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13871901 + ... + 13873450.

Almost surely, 2^21502647025 is an apocalyptic number.

21502647025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21502647025 is a deficient number, since it is larger than the sum of its proper divisors (6020742159).

21502647025 is a wasteful number, since it uses less digits than its factorization.

21502647025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27745392 (or 27745387 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 34.

The spelling of 21502647025 in words is "twenty-one billion, five hundred two million, six hundred forty-seven thousand, twenty-five".