31660987 has 4 divisors (see below), whose sum is σ = 33523416. Its totient is φ = 29798560.

The previous prime is 31660963. The next prime is 31660991. The reversal of 31660987 is 78906613.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78906613 = 2351 ⋅33563.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31660987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31660927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 931189 + ... + 931222.

It is an arithmetic number, because the mean of its divisors is an integer number (8380854).

Almost surely, 2^31660987 is an apocalyptic number.

31660987 is a deficient number, since it is larger than the sum of its proper divisors (1862429).

31660987 is a wasteful number, since it uses less digits than its factorization.

31660987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1862428.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 31660987 is about 5626.8096644546. The cubic root of 31660987 is about 316.3550827453.

The spelling of 31660987 in words is "thirty-one million, six hundred sixty thousand, nine hundred eighty-seven".