251400042 has 12 divisors (see below), whose sum is σ = 544700130. Its totient is φ = 83800008.

The previous prime is 251399999. The next prime is 251400047. The reversal of 251400042 is 240004152.

It can be written as a sum of positive squares in only one way, i.e., 224370441 + 27029601 = 14979^2 + 5199^2 .

It is a super-2 number, since 2×251400042² = 126403962235203528, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 13966669 = 251400042 / (2 + 5 + 1 + 4 + 0 + 0 + 0 + 4 + 2).

It is a junction number, because it is equal to n+sod(n) for n = 251399988 and 251400024.

It is not an unprimeable number, because it can be changed into a prime (251400047) 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, 6983317 + ... + 6983352.

Almost surely, 2^251400042 is an apocalyptic number.

251400042 is an abundant number, since it is smaller than the sum of its proper divisors (293300088).

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

251400042 is a wasteful number, since it uses less digits than its factorization.

251400042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13966677 (or 13966674 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 251400042 is about 15855.5997048361. The cubic root of 251400042 is about 631.1342981486.

Adding to 251400042 its reverse (240004152), we get a palindrome (491404194).

The spelling of 251400042 in words is "two hundred fifty-one million, four hundred thousand, forty-two".