21388943725 has 24 divisors (see below), whose sum is σ = 27685281600. Its totient is φ = 16361368320.

The previous prime is 21388943677. The next prime is 21388943731. The reversal of 21388943725 is 52734988312.

It is a happy number.

It is not a de Polignac number, because 21388943725 - 2³³ = 12799009133 is a prime.

It is a hoax number, since the sum of its digits (52) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2323582 + ... + 2332768.

It is an arithmetic number, because the mean of its divisors is an integer number (1153553400).

Almost surely, 2^21388943725 is an apocalyptic number.

21388943725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21388943725 is a deficient number, since it is larger than the sum of its proper divisors (6296337875).

21388943725 is a wasteful number, since it uses less digits than its factorization.

21388943725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13269 (or 13264 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 52.

The spelling of 21388943725 in words is "twenty-one billion, three hundred eighty-eight million, nine hundred forty-three thousand, seven hundred twenty-five".