251440425 has 18 divisors (see below), whose sum is σ = 450358142. Its totient is φ = 134101440.

The previous prime is 251440403. The next prime is 251440429. The reversal of 251440425 is 524044152.

251440425 is a `hidden beast` number, since 251 + 4 + 404 + 2 + 5 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 4981824 + 246458601 = 2232^2 + 15699^2 .

It is not a de Polignac number, because 251440425 - 2²¹ = 249343273 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (251440429) 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 17 ways as a sum of consecutive naturals, for example, 558532 + ... + 558981.

Almost surely, 2^251440425 is an apocalyptic number.

251440425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

251440425 is a deficient number, since it is larger than the sum of its proper divisors (198917717).

251440425 is a wasteful number, since it uses less digits than its factorization.

251440425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1117529 (or 1117521 counting only the distinct ones).

The product of its (nonzero) digits is 6400, while the sum is 27.

The square root of 251440425 is about 15856.8731154664. The cubic root of 251440425 is about 631.1680898849.

Adding to 251440425 its reverse (524044152), we get a palindrome (775484577).

The spelling of 251440425 in words is "two hundred fifty-one million, four hundred forty thousand, four hundred twenty-five".