251816161072720 has 80 divisors (see below), whose sum is σ = 586671450981120. Its totient is φ = 100520416563200.

The previous prime is 251816161072673. The next prime is 251816161072733. The reversal of 251816161072720 is 27270161618152.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×251816161072720² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74980725 + ... + 78267115.

It is an arithmetic number, because the mean of its divisors is an integer number (7333393137264).

Almost surely, 2^{251816161072720} is an apocalyptic number.

251816161072720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251816161072720 is an abundant number, since it is smaller than the sum of its proper divisors (334855289908400).

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

251816161072720 is a wasteful number, since it uses less digits than its factorization.

251816161072720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3288364 (or 3288358 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 49.

The spelling of 251816161072720 in words is "two hundred fifty-one trillion, eight hundred sixteen billion, one hundred sixty-one million, seventy-two thousand, seven hundred twenty".