31998997 has 4 divisors (see below), whose sum is σ = 32033056. Its totient is φ = 31964940.

The previous prime is 31998991. The next prime is 31999007. The reversal of 31998997 is 79989913.

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 a de Polignac number, because none of the positive numbers 2^k-31998997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31998991) 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, 15579 + ... + 17512.

It is an arithmetic number, because the mean of its divisors is an integer number (8008264).

Almost surely, 2^31998997 is an apocalyptic number.

It is an amenable number.

31998997 is a deficient number, since it is larger than the sum of its proper divisors (34059).

31998997 is an equidigital number, since it uses as much as digits as its factorization.

31998997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34058.

The product of its digits is 1102248, while the sum is 55.

The square root of 31998997 is about 5656.7655952850. The cubic root of 31998997 is about 317.4768933522.

It can be divided in two parts, 3 and 1998997, that added together give a triangular number (1999000 = T₁₉₉₉).

The spelling of 31998997 in words is "thirty-one million, nine hundred ninety-eight thousand, nine hundred ninety-seven".