661706396250 has 80 divisors (see below), whose sum is σ = 1663640814528. Its totient is φ = 175398256000.

The previous prime is 661706396243. The next prime is 661706396261. The reversal of 661706396250 is 52693607166.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 661706396193 and 661706396202.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 97942 + ... + 1154558.

Almost surely, 2^661706396250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661706396250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (831820407264).

661706396250 is an abundant number, since it is smaller than the sum of its proper divisors (1001934418278).

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

661706396250 is a wasteful number, since it uses less digits than its factorization.

661706396250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1056809 (or 1056794 counting only the distinct ones).

The product of its (nonzero) digits is 2449440, while the sum is 51.

The spelling of 661706396250 in words is "six hundred sixty-one billion, seven hundred six million, three hundred ninety-six thousand, two hundred fifty".