31666644 has 18 divisors (see below), whose sum is σ = 80046330. Its totient is φ = 10555536.

The previous prime is 31666643. The next prime is 31666693. The reversal of 31666644 is 44666613.

It can be written as a sum of positive squares in only one way, i.e., 29811600 + 1855044 = 5460^2 + 1362^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 879629 = 31666644 / (3 + 1 + 6 + 6 + 6 + 6 + 4 + 4).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 31666599 and 31666608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31666643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 439779 + ... + 439850.

Almost surely, 2^31666644 is an apocalyptic number.

It is an amenable number.

31666644 is an abundant number, since it is smaller than the sum of its proper divisors (48379686).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31666644 is a wasteful number, since it uses less digits than its factorization.

31666644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 879639 (or 879634 counting only the distinct ones).

The product of its digits is 62208, while the sum is 36.

The square root of 31666644 is about 5627.3123247248. The cubic root of 31666644 is about 316.3739231152.

The spelling of 31666644 in words is "thirty-one million, six hundred sixty-six thousand, six hundred forty-four".