661181982 has 8 divisors (see below), whose sum is σ = 1322363976. Its totient is φ = 220393992.

The previous prime is 661181977. The next prime is 661181993. The reversal of 661181982 is 289181166.

It is a sphenic number, since it is the product of 3 distinct primes.

661181982 is an admirable number.

It is a super-2 number, since 2×661181982² = 874323226642896648, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55098493 + ... + 55098504.

It is an arithmetic number, because the mean of its divisors is an integer number (165295497).

Almost surely, 2^661181982 is an apocalyptic number.

661181982 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

661181982 is a wasteful number, since it uses less digits than its factorization.

661181982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 110197002.

The product of its digits is 41472, while the sum is 42.

The square root of 661181982 is about 25713.4591605253. The cubic root of 661181982 is about 871.1782081425.

The spelling of 661181982 in words is "six hundred sixty-one million, one hundred eighty-one thousand, nine hundred eighty-two".