251661642 has 32 divisors (see below), whose sum is σ = 547342272. Its totient is φ = 76817664.

The previous prime is 251661601. The next prime is 251661691. The reversal of 251661642 is 246166152.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29568 + ... + 37115.

It is an arithmetic number, because the mean of its divisors is an integer number (17104446).

Almost surely, 2^251661642 is an apocalyptic number.

251661642 is an abundant number, since it is smaller than the sum of its proper divisors (295680630).

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

251661642 is a wasteful number, since it uses less digits than its factorization.

251661642 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66742.

The product of its digits is 17280, while the sum is 33.

The square root of 251661642 is about 15863.8470113652. The cubic root of 251661642 is about 631.3531359504.

The spelling of 251661642 in words is "two hundred fifty-one million, six hundred sixty-one thousand, six hundred forty-two".