253493721 has 12 divisors (see below), whose sum is σ = 394323748. Its totient is φ = 155996064.

The previous prime is 253493719. The next prime is 253493731. The reversal of 253493721 is 127394352.

It can be written as a sum of positive squares in 2 ways, for example, as 148718025 + 104775696 = 12195^2 + 10236^2 .

It is not a de Polignac number, because 253493721 - 2¹ = 253493719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (253493731) 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 11 ways as a sum of consecutive naturals, for example, 1083190 + ... + 1083423.

Almost surely, 2^253493721 is an apocalyptic number.

It is an amenable number.

253493721 is a deficient number, since it is larger than the sum of its proper divisors (140830027).

253493721 is a wasteful number, since it uses less digits than its factorization.

253493721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2166632 (or 2166629 counting only the distinct ones).

The product of its digits is 45360, while the sum is 36.

The square root of 253493721 is about 15921.4861429453. The cubic root of 253493721 is about 632.8815018932.

The spelling of 253493721 in words is "two hundred fifty-three million, four hundred ninety-three thousand, seven hundred twenty-one".