251481965 has 12 divisors (see below), whose sum is σ = 351048636. Its totient is φ = 172444608.

The previous prime is 251481961. The next prime is 251481973. The reversal of 251481965 is 569184152.

It can be written as a sum of positive squares in 2 ways, for example, as 75707401 + 175774564 = 8701^2 + 13258^2 .

It is not a de Polignac number, because 251481965 - 2² = 251481961 is a prime.

It is a super-2 number, since 2×251481965² = 126486357440522450, 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 (251481961) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 512984 + ... + 513473.

It is an arithmetic number, because the mean of its divisors is an integer number (29254053).

Almost surely, 2^251481965 is an apocalyptic number.

It is an amenable number.

251481965 is a deficient number, since it is larger than the sum of its proper divisors (99566671).

251481965 is a wasteful number, since it uses less digits than its factorization.

251481965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1026476 (or 1026469 counting only the distinct ones).

The product of its digits is 86400, while the sum is 41.

The square root of 251481965 is about 15858.1829034729. The cubic root of 251481965 is about 631.2028460023.

The spelling of 251481965 in words is "two hundred fifty-one million, four hundred eighty-one thousand, nine hundred sixty-five".