66615940 has 24 divisors (see below), whose sum is σ = 140098392. Its totient is φ = 26607360.

The previous prime is 66615937. The next prime is 66615959. The reversal of 66615940 is 4951666.

It can be written as a sum of positive squares in 4 ways, for example, as 2903616 + 63712324 = 1704^2 + 7982^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 66615940.

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, 14392 + ... + 18448.

It is an arithmetic number, because the mean of its divisors is an integer number (5837433).

Almost surely, 2^66615940 is an apocalyptic number.

It is an amenable number.

66615940 is an abundant number, since it is smaller than the sum of its proper divisors (73482452).

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

66615940 is a wasteful number, since it uses less digits than its factorization.

66615940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4887 (or 4885 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 37.

The square root of 66615940 is about 8161.8588569026. The cubic root of 66615940 is about 405.3772636650.

The spelling of 66615940 in words is "sixty-six million, six hundred fifteen thousand, nine hundred forty".