21857032025 has 6 divisors (see below), whose sum is σ = 27102719742. Its totient is φ = 17485625600.

The previous prime is 21857032009. The next prime is 21857032049. The reversal of 21857032025 is 52023075812.

It can be written as a sum of positive squares in 3 ways, for example, as 73633561 + 21783398464 = 8581^2 + 147592^2 .

It is not a de Polignac number, because 21857032025 - 2⁴ = 21857032009 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 437140616 + ... + 437140665.

It is an arithmetic number, because the mean of its divisors is an integer number (4517119957).

Almost surely, 2^21857032025 is an apocalyptic number.

21857032025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21857032025 is a deficient number, since it is larger than the sum of its proper divisors (5245687717).

21857032025 is an equidigital number, since it uses as much as digits as its factorization.

21857032025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874281291 (or 874281286 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 35.

The spelling of 21857032025 in words is "twenty-one billion, eight hundred fifty-seven million, thirty-two thousand, twenty-five".