251530042 has 4 divisors (see below), whose sum is σ = 377295066. Its totient is φ = 125765020.

The previous prime is 251530009. The next prime is 251530043. The reversal of 251530042 is 240035152.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 157226521 + 94303521 = 12539^2 + 9711^2 .

It is a junction number, because it is equal to n+sod(n) for n = 251529995 and 251530022.

It is not an unprimeable number, because it can be changed into a prime (251530043) 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 as a sum of consecutive naturals, namely, 62882509 + ... + 62882512.

Almost surely, 2^251530042 is an apocalyptic number.

251530042 is a deficient number, since it is larger than the sum of its proper divisors (125765024).

251530042 is a wasteful number, since it uses less digits than its factorization.

251530042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125765023.

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 251530042 is about 15859.6986730518. The cubic root of 251530042 is about 631.2430667866.

Adding to 251530042 its reverse (240035152), we get a palindrome (491565194).

The spelling of 251530042 in words is "two hundred fifty-one million, five hundred thirty thousand, forty-two".