31523987 has 4 divisors (see below), whose sum is σ = 34389816. Its totient is φ = 28658160.

The previous prime is 31523953. The next prime is 31524011. The reversal of 31523987 is 78932513.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 31523987 - 2¹⁶ = 31458451 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 31523987.

It is not an unprimeable number, because it can be changed into a prime (31523917) 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, 1432898 + ... + 1432919.

It is an arithmetic number, because the mean of its divisors is an integer number (8597454).

Almost surely, 2^31523987 is an apocalyptic number.

31523987 is a deficient number, since it is larger than the sum of its proper divisors (2865829).

31523987 is a wasteful number, since it uses less digits than its factorization.

31523987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2865828.

The product of its digits is 45360, while the sum is 38.

The square root of 31523987 is about 5614.6226053048. The cubic root of 31523987 is about 315.8981238383.

The spelling of 31523987 in words is "thirty-one million, five hundred twenty-three thousand, nine hundred eighty-seven".