31491073 has 4 divisors (see below), whose sum is σ = 32024880. Its totient is φ = 30957268.

The previous prime is 31491043. The next prime is 31491077. The reversal of 31491073 is 37019413.

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 an emirpimes, since its reverse is a distinct semiprime: 37019413 = 271 ⋅136603.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31491073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31491077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 266815 + ... + 266932.

It is an arithmetic number, because the mean of its divisors is an integer number (8006220).

Almost surely, 2^31491073 is an apocalyptic number.

It is an amenable number.

31491073 is a deficient number, since it is larger than the sum of its proper divisors (533807).

31491073 is an equidigital number, since it uses as much as digits as its factorization.

31491073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 533806.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 31491073 is about 5611.6907434391. The cubic root of 31491073 is about 315.7881431265.

The spelling of 31491073 in words is "thirty-one million, four hundred ninety-one thousand, seventy-three".