253667781 has 10 divisors (see below), whose sum is σ = 378935942. Its totient is φ = 169111800.

The previous prime is 253667767. The next prime is 253667783. The reversal of 253667781 is 187766352.

It can be written as a sum of positive squares in only one way, i.e., 235469025 + 18198756 = 15345^2 + 4266^2 .

It is not a de Polignac number, because 253667781 - 2⁵ = 253667749 is a prime.

It is a super-2 number, since 2×253667781² = 128694686234927922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (253667783) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1565770 + ... + 1565931.

Almost surely, 2^253667781 is an apocalyptic number.

It is an amenable number.

253667781 is a deficient number, since it is larger than the sum of its proper divisors (125268161).

253667781 is an equidigital number, since it uses as much as digits as its factorization.

253667781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3131713 (or 3131704 counting only the distinct ones).

The product of its digits is 423360, while the sum is 45.

The square root of 253667781 is about 15926.9514032033. The cubic root of 253667781 is about 633.0263235611.

The spelling of 253667781 in words is "two hundred fifty-three million, six hundred sixty-seven thousand, seven hundred eighty-one".