31297451993 has 4 divisors (see below), whose sum is σ = 31738261248. Its totient is φ = 30856642740.

The previous prime is 31297451981. The next prime is 31297452031. The reversal of 31297451993 is 39915479213.

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: 39915479213 = 109 ⋅366197057.

It is a cyclic number.

It is not a de Polignac number, because 31297451993 - 2¹⁰ = 31297450969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31297451593) 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, 220404521 + ... + 220404662.

It is an arithmetic number, because the mean of its divisors is an integer number (7934565312).

Almost surely, 2^31297451993 is an apocalyptic number.

It is an amenable number.

31297451993 is a deficient number, since it is larger than the sum of its proper divisors (440809255).

31297451993 is an equidigital number, since it uses as much as digits as its factorization.

31297451993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 440809254.

The product of its digits is 1837080, while the sum is 53.

The spelling of 31297451993 in words is "thirty-one billion, two hundred ninety-seven million, four hundred fifty-one thousand, nine hundred ninety-three".