251040720 has 120 divisors (see below), whose sum is σ = 905325984. Its totient is φ = 57378048.

The previous prime is 251040709. The next prime is 251040731. The reversal of 251040720 is 27040152.

It is an interprime number because it is at equal distance from previous prime (251040709) and next prime (251040731).

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1087 + ... + 22433.

Almost surely, 2^251040720 is an apocalyptic number.

251040720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251040720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (452662992).

251040720 is an abundant number, since it is smaller than the sum of its proper divisors (654285264).

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

251040720 is a wasteful number, since it uses less digits than its factorization.

251040720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21377 (or 21364 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 251040720 is about 15844.2645774425. The cubic root of 251040720 is about 630.8334647745.

Adding to 251040720 its reverse (27040152), we get a palindrome (278080872).

The spelling of 251040720 in words is "two hundred fifty-one million, forty thousand, seven hundred twenty".