66716638 has 8 divisors (see below), whose sum is σ = 105342120. Its totient is φ = 31602600.

The previous prime is 66716633. The next prime is 66716707. The reversal of 66716638 is 83661766.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×66716638² = 8902219572046088, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 66716594 and 66716603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66716633) 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, 877813 + ... + 877888.

It is an arithmetic number, because the mean of its divisors is an integer number (13167765).

Almost surely, 2^66716638 is an apocalyptic number.

66716638 is a deficient number, since it is larger than the sum of its proper divisors (38625482).

66716638 is a wasteful number, since it uses less digits than its factorization.

66716638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1755722.

The product of its digits is 217728, while the sum is 43.

The square root of 66716638 is about 8168.0253427619. The cubic root of 66716638 is about 405.5814196497.

The spelling of 66716638 in words is "sixty-six million, seven hundred sixteen thousand, six hundred thirty-eight".