66723643 has 6 divisors (see below), whose sum is σ = 77617356. Its totient is φ = 57191652.

The previous prime is 66723583. The next prime is 66723677. The reversal of 66723643 is 34632766.

It is not a de Polignac number, because 66723643 - 2²¹ = 64626491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66723443) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 680805 + ... + 680902.

It is an arithmetic number, because the mean of its divisors is an integer number (12936226).

Almost surely, 2^66723643 is an apocalyptic number.

66723643 is a deficient number, since it is larger than the sum of its proper divisors (10893713).

66723643 is a wasteful number, since it uses less digits than its factorization.

66723643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361721 (or 1361714 counting only the distinct ones).

The product of its digits is 108864, while the sum is 37.

The square root of 66723643 is about 8168.4541377179. The cubic root of 66723643 is about 405.5956140022.

It can be divided in two parts, 667 and 23643, that added together give a triangular number (24310 = T₂₂₀).

The spelling of 66723643 in words is "sixty-six million, seven hundred twenty-three thousand, six hundred forty-three".