251552421 has 6 divisors (see below), whose sum is σ = 363353510. Its totient is φ = 167701608.

The previous prime is 251552407. The next prime is 251552429. The reversal of 251552421 is 124255152.

It can be written as a sum of positive squares in only one way, i.e., 251381025 + 171396 = 15855^2 + 414^2 .

It is not a de Polignac number, because 251552421 - 2¹⁴ = 251536037 is a prime.

It is a super-2 number, since 2×251552421² = 126557241021922482, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251552429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 13975126 + ... + 13975143.

Almost surely, 2^251552421 is an apocalyptic number.

It is an amenable number.

251552421 is a deficient number, since it is larger than the sum of its proper divisors (111801089).

251552421 is a wasteful number, since it uses less digits than its factorization.

251552421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27950275 (or 27950272 counting only the distinct ones).

The product of its digits is 4000, while the sum is 27.

The square root of 251552421 is about 15860.4041877879. The cubic root of 251552421 is about 631.2617871079.

The spelling of 251552421 in words is "two hundred fifty-one million, five hundred fifty-two thousand, four hundred twenty-one".