251816494650 has 192 divisors, whose sum is σ = 732468261888. Its totient is φ = 56053992960.

The previous prime is 251816494649. The next prime is 251816494651. The reversal of 251816494650 is 56494618152.

It is an interprime number because it is at equal distance from previous prime (251816494649) and next prime (251816494651).

It is a junction number, because it is equal to n+sod(n) for n = 251816494593 and 251816494602.

It is not an unprimeable number, because it can be changed into a prime (251816494651) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 15659014 + ... + 15675086.

It is an arithmetic number, because the mean of its divisors is an integer number (3814938864).

Almost surely, 2^251816494650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251816494650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (366234130944).

251816494650 is an abundant number, since it is smaller than the sum of its proper divisors (480651767238).

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

251816494650 is a wasteful number, since it uses less digits than its factorization.

251816494650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16485 (or 16480 counting only the distinct ones).

The product of its (nonzero) digits is 2073600, while the sum is 51.

The spelling of 251816494650 in words is "two hundred fifty-one billion, eight hundred sixteen million, four hundred ninety-four thousand, six hundred fifty".