251665120 has 96 divisors (see below), whose sum is σ = 697975488. Its totient is φ = 83939328.

The previous prime is 251665081. The next prime is 251665121. The reversal of 251665120 is 21566152.

It is a super-2 number, since 2×251665120² = 126670665249228800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251665121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38404 + ... + 44476.

It is an arithmetic number, because the mean of its divisors is an integer number (7270578).

Almost surely, 2^251665120 is an apocalyptic number.

251665120 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 251665120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (348987744).

251665120 is an abundant number, since it is smaller than the sum of its proper divisors (446310368).

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

251665120 is a wasteful number, since it uses less digits than its factorization.

251665120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6132 (or 6124 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 251665120 is about 15863.9566313073. The cubic root of 251665120 is about 631.3560444006.

The spelling of 251665120 in words is "two hundred fifty-one million, six hundred sixty-five thousand, one hundred twenty".