31978697 has 2 divisors, whose sum is σ = 31978698. Its totient is φ = 31978696.

The previous prime is 31978673. The next prime is 31978699. The reversal of 31978697 is 79687913.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27994681 + 3984016 = 5291^2 + 1996^2 .

It is an emirp because it is prime and its reverse (79687913) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31978697 - 2⁶ = 31978633 is a prime.

Together with 31978699, 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 (31978699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15989348 + 15989349.

It is an arithmetic number, because the mean of its divisors is an integer number (15989349).

Almost surely, 2^31978697 is an apocalyptic number.

It is an amenable number.

31978697 is a deficient number, since it is larger than the sum of its proper divisors (1).

31978697 is an equidigital number, since it uses as much as digits as its factorization.

31978697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 571536, while the sum is 50.

The square root of 31978697 is about 5654.9709990415. The cubic root of 31978697 is about 317.4097439114.

The spelling of 31978697 in words is "thirty-one million, nine hundred seventy-eight thousand, six hundred ninety-seven".