251230220540 has 48 divisors (see below), whose sum is σ = 568280935488. Its totient is φ = 92743294464.

The previous prime is 251230220531. The next prime is 251230220543. The reversal of 251230220540 is 45022032152.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251230220543) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1234889 + ... + 1423871.

It is an arithmetic number, because the mean of its divisors is an integer number (11839186156).

Almost surely, 2^251230220540 is an apocalyptic number.

251230220540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

251230220540 is an abundant number, since it is smaller than the sum of its proper divisors (317050714948).

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

251230220540 is a wasteful number, since it uses less digits than its factorization.

251230220540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194118 (or 194116 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 26.

Adding to 251230220540 its reverse (45022032152), we get a palindrome (296252252692).

The spelling of 251230220540 in words is "two hundred fifty-one billion, two hundred thirty million, two hundred twenty thousand, five hundred forty".