253416635721 has 20 divisors (see below), whose sum is σ = 385703313732. Its totient is φ = 165756790368.

The previous prime is 253416635707. The next prime is 253416635723. The reversal of 253416635721 is 127536614352.

253416635721 is a `hidden beast` number, since 2 + 5 + 3 + 4 + 1 + 6 + 635 + 7 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 124334517321 + 129082118400 = 352611^2 + 359280^2 .

It is not a de Polignac number, because 253416635721 - 2²¹ = 253414538569 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (253416635723) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 29510806 + ... + 29519391.

Almost surely, 2^253416635721 is an apocalyptic number.

It is an amenable number.

253416635721 is a deficient number, since it is larger than the sum of its proper divisors (132286678011).

253416635721 is an equidigital number, since it uses as much as digits as its factorization.

253416635721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59030262 (or 59030253 counting only the distinct ones).

The product of its digits is 907200, while the sum is 45.

The spelling of 253416635721 in words is "two hundred fifty-three billion, four hundred sixteen million, six hundred thirty-five thousand, seven hundred twenty-one".