251661300000 has 288 divisors, whose sum is σ = 900787220928. Its totient is φ = 61008000000.

The previous prime is 251661299999. The next prime is 251661300029. The reversal of 251661300000 is 3166152.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3261870 + ... + 3338130.

It is an arithmetic number, because the mean of its divisors is an integer number (3127733406).

Almost surely, 2^251661300000 is an apocalyptic number.

251661300000 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 251661300000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (450393610464).

251661300000 is an abundant number, since it is smaller than the sum of its proper divisors (649125920928).

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

251661300000 is an equidigital number, since it uses as much as digits as its factorization.

251661300000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76310 (or 76282 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 24.

Adding to 251661300000 its reverse (3166152), we get a palindrome (251664466152).

The spelling of 251661300000 in words is "two hundred fifty-one billion, six hundred sixty-one million, three hundred thousand".