251351021442340 has 24 divisors (see below), whose sum is σ = 546038425893240. Its totient is φ = 97073497936128.

The previous prime is 251351021442331. The next prime is 251351021442343. The reversal of 251351021442340 is 43244120153152.

It can be written as a sum of positive squares in 4 ways, for example, as 52172220165156 + 199178801277184 = 7223034^2 + 14113072^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 251351021442340.

It is not an unprimeable number, because it can be changed into a prime (251351021442343) 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, 216681914457 + ... + 216681915616.

It is an arithmetic number, because the mean of its divisors is an integer number (22751601078885).

Almost surely, 2^{251351021442340} is an apocalyptic number.

251351021442340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251351021442340 is an abundant number, since it is smaller than the sum of its proper divisors (294687404450900).

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

251351021442340 is a wasteful number, since it uses less digits than its factorization.

251351021442340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 433363830111 (or 433363830109 counting only the distinct ones).

The product of its (nonzero) digits is 115200, while the sum is 37.

Adding to 251351021442340 its reverse (43244120153152), we get a palindrome (294595141595492).

The spelling of 251351021442340 in words is "two hundred fifty-one trillion, three hundred fifty-one billion, twenty-one million, four hundred forty-two thousand, three hundred forty".