251421972 has 12 divisors (see below), whose sum is σ = 586651296. Its totient is φ = 83807320.

The previous prime is 251421953. The next prime is 251421977. The reversal of 251421972 is 279124152.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251421977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10475904 + ... + 10475927.

It is an arithmetic number, because the mean of its divisors is an integer number (48887608).

Almost surely, 2^251421972 is an apocalyptic number.

It is an amenable number.

251421972 is an abundant number, since it is smaller than the sum of its proper divisors (335229324).

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

251421972 is a wasteful number, since it uses less digits than its factorization.

251421972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20951838 (or 20951836 counting only the distinct ones).

The product of its digits is 10080, while the sum is 33.

The square root of 251421972 is about 15856.2912435412. The cubic root of 251421972 is about 631.1526492099.

The spelling of 251421972 in words is "two hundred fifty-one million, four hundred twenty-one thousand, nine hundred seventy-two".