251532240 has 40 divisors (see below), whose sum is σ = 779750688. Its totient is φ = 67075200.

The previous prime is 251532199. The next prime is 251532257. The reversal of 251532240 is 42235152.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 251532240.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 523786 + ... + 524265.

Almost surely, 2^251532240 is an apocalyptic number.

251532240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251532240 is an abundant number, since it is smaller than the sum of its proper divisors (528218448).

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

251532240 is a wasteful number, since it uses less digits than its factorization.

251532240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1048067 (or 1048061 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 251532240 is about 15859.7679680379. The cubic root of 251532240 is about 631.2449054910.

Adding to 251532240 its reverse (42235152), we get a palindrome (293767392).

The spelling of 251532240 in words is "two hundred fifty-one million, five hundred thirty-two thousand, two hundred forty".