31681661 has 8 divisors (see below), whose sum is σ = 34815744. Its totient is φ = 28589920.

The previous prime is 31681633. The next prime is 31681673. The reversal of 31681661 is 16618613.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 31681661 - 2¹⁸ = 31419517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31681621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9005 + ... + 12018.

It is an arithmetic number, because the mean of its divisors is an integer number (4351968).

Almost surely, 2^31681661 is an apocalyptic number.

It is an amenable number.

31681661 is a deficient number, since it is larger than the sum of its proper divisors (3134083).

31681661 is a wasteful number, since it uses less digits than its factorization.

31681661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21171.

The product of its digits is 5184, while the sum is 32.

The square root of 31681661 is about 5628.6464625165. The cubic root of 31681661 is about 316.4239256394.

The spelling of 31681661 in words is "thirty-one million, six hundred eighty-one thousand, six hundred sixty-one".