31791397 has 4 divisors (see below), whose sum is σ = 34681536. Its totient is φ = 28901260.

The previous prime is 31791391. The next prime is 31791413. The reversal of 31791397 is 79319713.

It is a happy number.

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-31791397 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 (31791391) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1445053 + ... + 1445074.

It is an arithmetic number, because the mean of its divisors is an integer number (8670384).

Almost surely, 2^31791397 is an apocalyptic number.

It is an amenable number.

31791397 is a deficient number, since it is larger than the sum of its proper divisors (2890139).

31791397 is a wasteful number, since it uses less digits than its factorization.

31791397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2890138.

The product of its digits is 35721, while the sum is 40.

The square root of 31791397 is about 5638.3860279339. The cubic root of 31791397 is about 316.7888379321.

The spelling of 31791397 in words is "thirty-one million, seven hundred ninety-one thousand, three hundred ninety-seven".