66637731 has 16 divisors (see below), whose sum is σ = 94928000. Its totient is φ = 41456448.

The previous prime is 66637721. The next prime is 66637757. The reversal of 66637731 is 13773666.

It is not a de Polignac number, because 66637731 - 2⁵ = 66637699 is a prime.

It is a super-2 number, since 2×66637731² = 8881174385656722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66637731.

It is not an unprimeable number, because it can be changed into a prime (66637721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4906 + ... + 12543.

It is an arithmetic number, because the mean of its divisors is an integer number (5933000).

Almost surely, 2^66637731 is an apocalyptic number.

66637731 is a deficient number, since it is larger than the sum of its proper divisors (28290269).

66637731 is a wasteful number, since it uses less digits than its factorization.

66637731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17538.

The product of its digits is 95256, while the sum is 39.

The square root of 66637731 is about 8163.1936764970. The cubic root of 66637731 is about 405.4214603589.

The spelling of 66637731 in words is "sixty-six million, six hundred thirty-seven thousand, seven hundred thirty-one".