251224135140 has 96 divisors (see below), whose sum is σ = 769041060480. Its totient is φ = 60770636800.

The previous prime is 251224135103. The next prime is 251224135189. The reversal of 251224135140 is 41531422152.

It is a super-2 number, since 2×251224135140² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 251224135098 and 251224135107.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 108585 + ... + 717104.

It is an arithmetic number, because the mean of its divisors is an integer number (8010844380).

Almost surely, 2^251224135140 is an apocalyptic number.

251224135140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251224135140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (384520530240).

251224135140 is an abundant number, since it is smaller than the sum of its proper divisors (517816925340).

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

251224135140 is a wasteful number, since it uses less digits than its factorization.

251224135140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 826173 (or 826171 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

Adding to 251224135140 its reverse (41531422152), we get a palindrome (292755557292).

The spelling of 251224135140 in words is "two hundred fifty-one billion, two hundred twenty-four million, one hundred thirty-five thousand, one hundred forty".