21122100725 has 12 divisors (see below), whose sum is σ = 28572442080. Its totient is φ = 15361527600.

The previous prime is 21122100707. The next prime is 21122100743. The reversal of 21122100725 is 52700122112.

It is an interprime number because it is at equal distance from previous prime (21122100707) and next prime (21122100743).

It is not a de Polignac number, because 21122100725 - 2²⁰ = 21121052149 is a prime.

It is a super-2 number, since 2×21122100725² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21122100725.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38403545 + ... + 38404094.

It is an arithmetic number, because the mean of its divisors is an integer number (2381036840).

Almost surely, 2^21122100725 is an apocalyptic number.

21122100725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21122100725 is a deficient number, since it is larger than the sum of its proper divisors (7450341355).

21122100725 is a wasteful number, since it uses less digits than its factorization.

21122100725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76807660 (or 76807655 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 23.

Adding to 21122100725 its reverse (52700122112), we get a palindrome (73822222837).

The spelling of 21122100725 in words is "twenty-one billion, one hundred twenty-two million, one hundred thousand, seven hundred twenty-five".