31780023971 has 2 divisors, whose sum is σ = 31780023972. Its totient is φ = 31780023970.

The previous prime is 31780023917. The next prime is 31780023973. The reversal of 31780023971 is 17932008713.

Together with previous prime (31780023917) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31780023971 is a prime.

Together with 31780023973, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31780023973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15890011985 + 15890011986.

It is an arithmetic number, because the mean of its divisors is an integer number (15890011986).

Almost surely, 2^31780023971 is an apocalyptic number.

31780023971 is a deficient number, since it is larger than the sum of its proper divisors (1).

31780023971 is an equidigital number, since it uses as much as digits as its factorization.

31780023971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 63504, while the sum is 41.

The spelling of 31780023971 in words is "thirty-one billion, seven hundred eighty million, twenty-three thousand, nine hundred seventy-one".