251406978 has 32 divisors (see below), whose sum is σ = 509379840. Its totient is φ = 82713600.

The previous prime is 251406943. The next prime is 251406979. The reversal of 251406978 is 879604152.

251406978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (251406979) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 349303 + ... + 350021.

It is an arithmetic number, because the mean of its divisors is an integer number (15918120).

Almost surely, 2^251406978 is an apocalyptic number.

251406978 is an abundant number, since it is smaller than the sum of its proper divisors (257972862).

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

251406978 is a wasteful number, since it uses less digits than its factorization.

251406978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1402.

The product of its (nonzero) digits is 120960, while the sum is 42.

The square root of 251406978 is about 15855.8184273156. The cubic root of 251406978 is about 631.1401023206.

It can be divided in two parts, 25 and 1406978, that added together give a triangular number (1407003 = T₁₆₇₇).

The spelling of 251406978 in words is "two hundred fifty-one million, four hundred six thousand, nine hundred seventy-eight".