251278537620 has 96 divisors (see below), whose sum is σ = 786262329216. Its totient is φ = 59430246400.

The previous prime is 251278537619. The next prime is 251278537621. The reversal of 251278537620 is 26735872152.

It is an interprime number because it is at equal distance from previous prime (251278537619) and next prime (251278537621).

It is a self number, because there is not a number n which added to its sum of digits gives 251278537620.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251278537621) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4615929 + ... + 4670048.

It is an arithmetic number, because the mean of its divisors is an integer number (8190232596).

Almost surely, 2^251278537620 is an apocalyptic number.

251278537620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251278537620 is an abundant number, since it is smaller than the sum of its proper divisors (534983791596).

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

251278537620 is a wasteful number, since it uses less digits than its factorization.

251278537620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9286041 (or 9286039 counting only the distinct ones).

The product of its (nonzero) digits is 1411200, while the sum is 48.

The spelling of 251278537620 in words is "two hundred fifty-one billion, two hundred seventy-eight million, five hundred thirty-seven thousand, six hundred twenty".