661094980 has 192 divisors, whose sum is σ = 1889879040. Its totient is φ = 188153856.

The previous prime is 661094969. The next prime is 661095011. The reversal of 661094980 is 89490166.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 711156 + ... + 712084.

It is an arithmetic number, because the mean of its divisors is an integer number (9843120).

Almost surely, 2^661094980 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 661094980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (944939520).

661094980 is an abundant number, since it is smaller than the sum of its proper divisors (1228784060).

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

661094980 is a wasteful number, since it uses less digits than its factorization.

661094980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998 (or 996 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 43.

The square root of 661094980 is about 25711.7673449337. The cubic root of 661094980 is about 871.1399949762.

The spelling of 661094980 in words is "six hundred sixty-one million, ninety-four thousand, nine hundred eighty".