251155213242 has 16 divisors (see below), whose sum is σ = 505681639200. Its totient is φ = 83156535632.

The previous prime is 251155213193. The next prime is 251155213247. The reversal of 251155213242 is 242312551152.

It is a super-2 number, since 2×251155213242² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (251155213247) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140466228 + ... + 140468015.

It is an arithmetic number, because the mean of its divisors is an integer number (31605102450).

Almost surely, 2^251155213242 is an apocalyptic number.

251155213242 is an abundant number, since it is smaller than the sum of its proper divisors (254526425958).

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

251155213242 is a wasteful number, since it uses less digits than its factorization.

251155213242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280934397.

The product of its digits is 24000, while the sum is 33.

Adding to 251155213242 its reverse (242312551152), we get a palindrome (493467764394).

The spelling of 251155213242 in words is "two hundred fifty-one billion, one hundred fifty-five million, two hundred thirteen thousand, two hundred forty-two".