661919885 has 8 divisors (see below), whose sum is σ = 866513376. Its totient is φ = 481396240.

The previous prime is 661919861. The next prime is 661919893. The reversal of 661919885 is 588919166.

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

It is not a de Polignac number, because 661919885 - 2²² = 657725581 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6017399 + ... + 6017508.

It is an arithmetic number, because the mean of its divisors is an integer number (108314172).

Almost surely, 2^661919885 is an apocalyptic number.

It is an amenable number.

661919885 is a deficient number, since it is larger than the sum of its proper divisors (204593491).

661919885 is a wasteful number, since it uses less digits than its factorization.

661919885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12034923.

The product of its digits is 933120, while the sum is 53.

The square root of 661919885 is about 25727.8037344815. The cubic root of 661919885 is about 871.5021764462.

The spelling of 661919885 in words is "six hundred sixty-one million, nine hundred nineteen thousand, eight hundred eighty-five".