21356022725 has 24 divisors (see below), whose sum is σ = 27041963400. Its totient is φ = 16724664320.

The previous prime is 21356022719. The next prime is 21356022731. The reversal of 21356022725 is 52722065312.

It is an interprime number because it is at equal distance from previous prime (21356022719) and next prime (21356022731).

It can be written as a sum of positive squares in 12 ways, for example, as 1536169636 + 19819853089 = 39194^2 + 140783^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21356022725 is a prime.

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, 576977 + ... + 612873.

It is an arithmetic number, because the mean of its divisors is an integer number (1126748475).

Almost surely, 2^21356022725 is an apocalyptic number.

21356022725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21356022725 is a deficient number, since it is larger than the sum of its proper divisors (5685940675).

21356022725 is a wasteful number, since it uses less digits than its factorization.

21356022725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36409 (or 36404 counting only the distinct ones).

The product of its (nonzero) digits is 50400, while the sum is 35.

The spelling of 21356022725 in words is "twenty-one billion, three hundred fifty-six million, twenty-two thousand, seven hundred twenty-five".