251442540 has 36 divisors (see below), whose sum is σ = 762709584. Its totient is φ = 67051296.

The previous prime is 251442511. The next prime is 251442589. The reversal of 251442540 is 45244152.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 698272 + ... + 698631.

Almost surely, 2^251442540 is an apocalyptic number.

251442540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251442540 is an abundant number, since it is smaller than the sum of its proper divisors (511267044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

251442540 is a wasteful number, since it uses less digits than its factorization.

251442540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1396918 (or 1396913 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 27.

The square root of 251442540 is about 15856.9398056498. The cubic root of 251442540 is about 631.1698595775.

Adding to 251442540 its reverse (45244152), we get a palindrome (296686692).

It can be divided in two parts, 2514 and 42540, that added together give a palindrome (45054).

The spelling of 251442540 in words is "two hundred fifty-one million, four hundred forty-two thousand, five hundred forty".