253904721 has 32 divisors (see below), whose sum is σ = 396902400. Its totient is φ = 144316368.

The previous prime is 253904711. The next prime is 253904737. The reversal of 253904721 is 127409352.

It is not a de Polignac number, because 253904721 - 2¹⁴ = 253888337 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (253904701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 233040 + ... + 234126.

It is an arithmetic number, because the mean of its divisors is an integer number (12403200).

Almost surely, 2^253904721 is an apocalyptic number.

253904721 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

253904721 is a deficient number, since it is larger than the sum of its proper divisors (142997679).

253904721 is a wasteful number, since it uses less digits than its factorization.

253904721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1338 (or 1324 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 253904721 is about 15934.3880020539. The cubic root of 253904721 is about 633.2233563116.

The spelling of 253904721 in words is "two hundred fifty-three million, nine hundred four thousand, seven hundred twenty-one".