31378091 has 2 divisors, whose sum is σ = 31378092. Its totient is φ = 31378090.

The previous prime is 31378051. The next prime is 31378097. The reversal of 31378091 is 19087313.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 31378091 - 2⁶ = 31378027 is a prime.

It is equal to p_1937831 and since 31378091 and 1937831 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (31378097) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15689045 + 15689046.

It is an arithmetic number, because the mean of its divisors is an integer number (15689046).

Almost surely, 2^31378091 is an apocalyptic number.

31378091 is a deficient number, since it is larger than the sum of its proper divisors (1).

31378091 is an equidigital number, since it uses as much as digits as its factorization.

31378091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 31378091 is about 5601.6150349698. The cubic root of 31378091 is about 315.4100346006.

The spelling of 31378091 in words is "thirty-one million, three hundred seventy-eight thousand, ninety-one".