661869798336 has 336 divisors, whose sum is σ = 2117151528960. Its totient is φ = 196798740480.

The previous prime is 661869798329. The next prime is 661869798371. The reversal of 661869798336 is 633897968166.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

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, 12526405 + ... + 12579131.

Almost surely, 2^661869798336 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661869798336, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1058575764480).

661869798336 is an abundant number, since it is smaller than the sum of its proper divisors (1455281730624).

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

661869798336 is a wasteful number, since it uses less digits than its factorization.

661869798336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52832 (or 52819 counting only the distinct ones).

The product of its digits is 423263232, while the sum is 72.

The spelling of 661869798336 in words is "six hundred sixty-one billion, eight hundred sixty-nine million, seven hundred ninety-eight thousand, three hundred thirty-six".