31661643 has 24 divisors (see below), whose sum is σ = 46089648. Its totient is φ = 19324032.

The previous prime is 31661611. The next prime is 31661681. The reversal of 31661643 is 34616613.

It is not a de Polignac number, because 31661643 - 2⁵ = 31661611 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31661643.

It is not an unprimeable number, because it can be changed into a prime (31665643) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 99721 + ... + 100037.

It is an arithmetic number, because the mean of its divisors is an integer number (1920402).

Almost surely, 2^31661643 is an apocalyptic number.

31661643 is a deficient number, since it is larger than the sum of its proper divisors (14428005).

31661643 is a wasteful number, since it uses less digits than its factorization.

31661643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543 (or 530 counting only the distinct ones).

The product of its digits is 7776, while the sum is 30.

The square root of 31661643 is about 5626.8679565101. The cubic root of 31661643 is about 316.3572676371.

The spelling of 31661643 in words is "thirty-one million, six hundred sixty-one thousand, six hundred forty-three".