66716651 has 4 divisors (see below), whose sum is σ = 66829752. Its totient is φ = 66603552.

The previous prime is 66716633. The next prime is 66716707. The reversal of 66716651 is 15661766.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15661766 = 2 ⋅7830883.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66716651 is a prime.

It is a super-2 number, since 2×66716651² = 8902223041311602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66716621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55661 + ... + 56846.

It is an arithmetic number, because the mean of its divisors is an integer number (16707438).

Almost surely, 2^66716651 is an apocalyptic number.

66716651 is a deficient number, since it is larger than the sum of its proper divisors (113101).

66716651 is a wasteful number, since it uses less digits than its factorization.

66716651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113100.

The product of its digits is 45360, while the sum is 38.

The square root of 66716651 is about 8168.0261385478. The cubic root of 66716651 is about 405.5814459928.

The spelling of 66716651 in words is "sixty-six million, seven hundred sixteen thousand, six hundred fifty-one".