251262334640 has 80 divisors (see below), whose sum is σ = 597043536768. Its totient is φ = 98295779328.

The previous prime is 251262334639. The next prime is 251262334643. The reversal of 251262334640 is 46433262152.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 251262334594 and 251262334603.

It is not an unprimeable number, because it can be changed into a prime (251262334643) 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, 5364764 + ... + 5411396.

Almost surely, 2^251262334640 is an apocalyptic number.

251262334640 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 251262334640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (298521768384).

251262334640 is an abundant number, since it is smaller than the sum of its proper divisors (345781202128).

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

251262334640 is a wasteful number, since it uses less digits than its factorization.

251262334640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48126 (or 48120 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 38.

Adding to 251262334640 its reverse (46433262152), we get a palindrome (297695596792).

The spelling of 251262334640 in words is "two hundred fifty-one billion, two hundred sixty-two million, three hundred thirty-four thousand, six hundred forty".