661918992 has 40 divisors (see below), whose sum is σ = 1954238016. Its totient is φ = 189119616.

The previous prime is 661918981. The next prime is 661919033. The reversal of 661918992 is 299819166.

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, 984663 + ... + 985334.

Almost surely, 2^661918992 is an apocalyptic number.

It is an amenable number.

661918992 is an abundant number, since it is smaller than the sum of its proper divisors (1292319024).

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

661918992 is a wasteful number, since it uses less digits than its factorization.

661918992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1970015 (or 1970009 counting only the distinct ones).

The product of its digits is 419904, while the sum is 51.

The square root of 661918992 is about 25727.7863797102. The cubic root of 661918992 is about 871.5017845298.

The spelling of 661918992 in words is "six hundred sixty-one million, nine hundred eighteen thousand, nine hundred ninety-two".