253585721 has 4 divisors (see below), whose sum is σ = 257059572. Its totient is φ = 250111872.

The previous prime is 253585693. The next prime is 253585729. The reversal of 253585721 is 127585352.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 194295721 + 59290000 = 13939^2 + 7700^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-253585721 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (253585729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1736816 + ... + 1736961.

It is an arithmetic number, because the mean of its divisors is an integer number (64264893).

Almost surely, 2^253585721 is an apocalyptic number.

It is an amenable number.

253585721 is a deficient number, since it is larger than the sum of its proper divisors (3473851).

253585721 is an equidigital number, since it uses as much as digits as its factorization.

253585721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3473850.

The product of its digits is 84000, while the sum is 38.

The square root of 253585721 is about 15924.3750583814. The cubic root of 253585721 is about 632.9580561310.

The spelling of 253585721 in words is "two hundred fifty-three million, five hundred eighty-five thousand, seven hundred twenty-one".