31987429 has 4 divisors (see below), whose sum is σ = 32019840. Its totient is φ = 31955020.

The previous prime is 31987427. The next prime is 31987433. The reversal of 31987429 is 92478913.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31987429 - 2¹ = 31987427 is a prime.

It is a super-2 number, since 2×31987429² = 2046391228060082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31987427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14677 + ... + 16714.

It is an arithmetic number, because the mean of its divisors is an integer number (8004960).

Almost surely, 2^31987429 is an apocalyptic number.

It is an amenable number.

31987429 is a deficient number, since it is larger than the sum of its proper divisors (32411).

31987429 is a wasteful number, since it uses less digits than its factorization.

31987429 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32410.

The product of its digits is 108864, while the sum is 43.

The square root of 31987429 is about 5655.7430104275. The cubic root of 31987429 is about 317.4386315764.

The spelling of 31987429 in words is "thirty-one million, nine hundred eighty-seven thousand, four hundred twenty-nine".