66749661 has 12 divisors (see below), whose sum is σ = 105181440. Its totient is φ = 40454280.

The previous prime is 66749659. The next prime is 66749671. The reversal of 66749661 is 16694766.

It is a happy number.

It is not a de Polignac number, because 66749661 - 2¹ = 66749659 is a prime.

It is a super-2 number, since 2×66749661² = 8911034487229842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66749671) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 337021 + ... + 337218.

It is an arithmetic number, because the mean of its divisors is an integer number (8765120).

Almost surely, 2^66749661 is an apocalyptic number.

It is an amenable number.

66749661 is a deficient number, since it is larger than the sum of its proper divisors (38431779).

66749661 is a wasteful number, since it uses less digits than its factorization.

66749661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 674256 (or 674253 counting only the distinct ones).

The product of its digits is 326592, while the sum is 45.

The square root of 66749661 is about 8170.0465726947. The cubic root of 66749661 is about 405.6483260288.

The spelling of 66749661 in words is "sixty-six million, seven hundred forty-nine thousand, six hundred sixty-one".