31661993 has 8 divisors (see below), whose sum is σ = 34858560. Its totient is φ = 28518480.

The previous prime is 31661983. The next prime is 31662013. The reversal of 31661993 is 39916613.

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 31661993 - 2⁸ = 31661737 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31661983) 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, 12005 + ... + 14402.

It is an arithmetic number, because the mean of its divisors is an integer number (4357320).

Almost surely, 2^31661993 is an apocalyptic number.

It is an amenable number.

31661993 is a deficient number, since it is larger than the sum of its proper divisors (3196567).

31661993 is a wasteful number, since it uses less digits than its factorization.

31661993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26527.

The product of its digits is 26244, while the sum is 38.

The square root of 31661993 is about 5626.8990572073. The cubic root of 31661993 is about 316.3584333445.

The spelling of 31661993 in words is "thirty-one million, six hundred sixty-one thousand, nine hundred ninety-three".