66723657 has 64 divisors (see below), whose sum is σ = 126572544. Its totient is φ = 30090240.

The previous prime is 66723583. The next prime is 66723677. The reversal of 66723657 is 75632766.

It is not a de Polignac number, because 66723657 - 2¹² = 66719561 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66723677) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 50398 + ... + 51704.

It is an arithmetic number, because the mean of its divisors is an integer number (1977696).

Almost surely, 2^66723657 is an apocalyptic number.

It is an amenable number.

66723657 is a deficient number, since it is larger than the sum of its proper divisors (59848887).

66723657 is a wasteful number, since it uses less digits than its factorization.

66723657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1358.

The product of its digits is 317520, while the sum is 42.

The square root of 66723657 is about 8168.4549946731. The cubic root of 66723657 is about 405.5956423696.

The spelling of 66723657 in words is "sixty-six million, seven hundred twenty-three thousand, six hundred fifty-seven".