31997219 has 4 divisors (see below), whose sum is σ = 32016144. Its totient is φ = 31978296.

The previous prime is 31997201. The next prime is 31997221. The reversal of 31997219 is 91279913.

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 31997219 - 2²⁴ = 15220003 is a prime.

It is a super-2 number, since 2×31997219² = 2047644047467922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31997249) 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, 6647 + ... + 10400.

It is an arithmetic number, because the mean of its divisors is an integer number (8004036).

Almost surely, 2^31997219 is an apocalyptic number.

31997219 is a deficient number, since it is larger than the sum of its proper divisors (18925).

31997219 is a wasteful number, since it uses less digits than its factorization.

31997219 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18924.

The product of its digits is 30618, while the sum is 41.

The square root of 31997219 is about 5656.6084361568. The cubic root of 31997219 is about 317.4710131224.

The spelling of 31997219 in words is "thirty-one million, nine hundred ninety-seven thousand, two hundred nineteen".