661673040 has 80 divisors (see below), whose sum is σ = 2344219008. Its totient is φ = 151239168.

The previous prime is 661673029. The next prime is 661673053. The reversal of 661673040 is 40376166.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×661673040² = 875622423725683200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661672992 and 661673010.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 195247 + ... + 198606.

Almost surely, 2^661673040 is an apocalyptic number.

661673040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

661673040 is an abundant number, since it is smaller than the sum of its proper divisors (1682545968).

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

661673040 is a wasteful number, since it uses less digits than its factorization.

661673040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393876 (or 393870 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 33.

The square root of 661673040 is about 25723.0060451729. The cubic root of 661673040 is about 871.3938286401.

The spelling of 661673040 in words is "six hundred sixty-one million, six hundred seventy-three thousand, forty".