31661997 has 16 divisors (see below), whose sum is σ = 43824000. Its totient is φ = 20309184.

The previous prime is 31661983. The next prime is 31662013. The reversal of 31661997 is 79916613.

It is not a de Polignac number, because 31661997 - 2¹⁴ = 31645613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31661957) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37779 + ... + 38607.

It is an arithmetic number, because the mean of its divisors is an integer number (2739000).

Almost surely, 2^31661997 is an apocalyptic number.

It is an amenable number.

31661997 is a deficient number, since it is larger than the sum of its proper divisors (12162003).

31661997 is a wasteful number, since it uses less digits than its factorization.

31661997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300.

The product of its digits is 61236, while the sum is 42.

The square root of 31661997 is about 5626.8994126428. The cubic root of 31661997 is about 316.3584466669.

The spelling of 31661997 in words is "thirty-one million, six hundred sixty-one thousand, nine hundred ninety-seven".