66491790 has 32 divisors (see below), whose sum is σ = 159805440. Its totient is φ = 17706144.

The previous prime is 66491783. The next prime is 66491819. The reversal of 66491790 is 9719466.

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, 31591 + ... + 33629.

It is an arithmetic number, because the mean of its divisors is an integer number (4993920).

Almost surely, 2^66491790 is an apocalyptic number.

66491790 is an abundant number, since it is smaller than the sum of its proper divisors (93313650).

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

66491790 is a wasteful number, since it uses less digits than its factorization.

66491790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3136.

The product of its (nonzero) digits is 81648, while the sum is 42.

The square root of 66491790 is about 8154.2498122145. The cubic root of 66491790 is about 405.1252775070.

The spelling of 66491790 in words is "sixty-six million, four hundred ninety-one thousand, seven hundred ninety".