251620164 has 18 divisors (see below), whose sum is σ = 636039950. Its totient is φ = 83873376.

The previous prime is 251620141. The next prime is 251620183. The reversal of 251620164 is 461026152.

251620164 is a `hidden beast` number, since 25 + 1 + 620 + 16 + 4 = 666.

It can be written as a sum of positive squares in only one way, i.e., 223741764 + 27878400 = 14958^2 + 5280^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3494689 + ... + 3494760.

Almost surely, 2^251620164 is an apocalyptic number.

It is an amenable number.

251620164 is an abundant number, since it is smaller than the sum of its proper divisors (384419786).

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

251620164 is a wasteful number, since it uses less digits than its factorization.

251620164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6989459 (or 6989454 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 251620164 is about 15862.5396453405. The cubic root of 251620164 is about 631.3184482324.

The spelling of 251620164 in words is "two hundred fifty-one million, six hundred twenty thousand, one hundred sixty-four".