21533554025 has 48 divisors (see below), whose sum is σ = 28034062848. Its totient is φ = 16388736000.

The previous prime is 21533554019. The next prime is 21533554073. The reversal of 21533554025 is 52045533512.

It is not a de Polignac number, because 21533554025 - 2¹⁰ = 21533553001 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11471387 + ... + 11473263.

It is an arithmetic number, because the mean of its divisors is an integer number (584042976).

Almost surely, 2^21533554025 is an apocalyptic number.

21533554025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21533554025 is a deficient number, since it is larger than the sum of its proper divisors (6500508823).

21533554025 is a wasteful number, since it uses less digits than its factorization.

21533554025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2162 (or 2157 counting only the distinct ones).

The product of its (nonzero) digits is 90000, while the sum is 35.

The spelling of 21533554025 in words is "twenty-one billion, five hundred thirty-three million, five hundred fifty-four thousand, twenty-five".