31398109 has 4 divisors (see below), whose sum is σ = 31410016. Its totient is φ = 31386204.

The previous prime is 31398091. The next prime is 31398113. The reversal of 31398109 is 90189313.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 31398109 - 2¹¹ = 31396061 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 (31398119) 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, 39 + ... + 7924.

It is an arithmetic number, because the mean of its divisors is an integer number (7852504).

Almost surely, 2^31398109 is an apocalyptic number.

It is an amenable number.

31398109 is a deficient number, since it is larger than the sum of its proper divisors (11907).

31398109 is an equidigital number, since it uses as much as digits as its factorization.

31398109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11906.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 31398109 is about 5603.4015561978. The cubic root of 31398109 is about 315.4770934484.

The spelling of 31398109 in words is "thirty-one million, three hundred ninety-eight thousand, one hundred nine".