251984421 has 48 divisors (see below), whose sum is σ = 418279680. Its totient is φ = 144806400.

The previous prime is 251984417. The next prime is 251984423. The reversal of 251984421 is 124489152.

251984421 is a `hidden beast` number, since 25 + 198 + 442 + 1 = 666.

251984421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 251984421 - 2² = 251984417 is a prime.

It is a super-2 number, since 2×251984421² = 126992296853410482, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251984423) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 299920 + ... + 300758.

It is an arithmetic number, because the mean of its divisors is an integer number (8714160).

Almost surely, 2^251984421 is an apocalyptic number.

It is an amenable number.

251984421 is a deficient number, since it is larger than the sum of its proper divisors (166295259).

251984421 is a wasteful number, since it uses less digits than its factorization.

251984421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1026 (or 1023 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 251984421 is about 15874.0171664264. The cubic root of 251984421 is about 631.6229432849.

It can be divided in two parts, 251984 and 421, that added together give a triangular number (252405 = T₇₁₀).

The spelling of 251984421 in words is "two hundred fifty-one million, nine hundred eighty-four thousand, four hundred twenty-one".