251661016 has 8 divisors (see below), whose sum is σ = 471864420. Its totient is φ = 125830504.

The previous prime is 251661001. The next prime is 251661031. The reversal of 251661016 is 610166152.

It is an interprime number because it is at equal distance from previous prime (251661001) and next prime (251661031).

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15728806 + ... + 15728821.

Almost surely, 2^251661016 is an apocalyptic number.

It is an amenable number.

251661016 is a deficient number, since it is larger than the sum of its proper divisors (220203404).

251661016 is a wasteful number, since it uses less digits than its factorization.

251661016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31457633 (or 31457629 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 251661016 is about 15863.8272809559. The cubic root of 251661016 is about 631.3526124599.

The spelling of 251661016 in words is "two hundred fifty-one million, six hundred sixty-one thousand, sixteen".