66491788 has 24 divisors (see below), whose sum is σ = 127149120. Its totient is φ = 30173520.

The previous prime is 66491783. The next prime is 66491819. The reversal of 66491788 is 88719466.

It is not an unprimeable number, because it can be changed into a prime (66491783) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44095 + ... + 45577.

It is an arithmetic number, because the mean of its divisors is an integer number (5297880).

Almost surely, 2^66491788 is an apocalyptic number.

It is an amenable number.

66491788 is a deficient number, since it is larger than the sum of its proper divisors (60657332).

66491788 is a wasteful number, since it uses less digits than its factorization.

66491788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2517 (or 2515 counting only the distinct ones).

The product of its digits is 580608, while the sum is 49.

The square root of 66491788 is about 8154.2496895790. The cubic root of 66491788 is about 405.1252734451.

The spelling of 66491788 in words is "sixty-six million, four hundred ninety-one thousand, seven hundred eighty-eight".