21100100025 has 24 divisors (see below), whose sum is σ = 34889668704. Its totient is φ = 11252041600.

The previous prime is 21100100017. The next prime is 21100100033. The reversal of 21100100025 is 52000100112.

It is an interprime number because it is at equal distance from previous prime (21100100017) and next prime (21100100033).

It is not a de Polignac number, because 21100100025 - 2³ = 21100100017 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1164082 + ... + 1182068.

It is an arithmetic number, because the mean of its divisors is an integer number (1453736196).

Almost surely, 2^21100100025 is an apocalyptic number.

21100100025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21100100025 is a deficient number, since it is larger than the sum of its proper divisors (13789568679).

21100100025 is a wasteful number, since it uses less digits than its factorization.

21100100025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33641 (or 33636 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 12.

Adding to 21100100025 its reverse (52000100112), we get a palindrome (73100200137).

The spelling of 21100100025 in words is "twenty-one billion, one hundred million, one hundred thousand, twenty-five".