31394021 has 2 divisors, whose sum is σ = 31394022. Its totient is φ = 31394020.

The previous prime is 31394017. The next prime is 31394059. The reversal of 31394021 is 12049313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25391521 + 6002500 = 5039^2 + 2450^2 .

It is an emirp because it is prime and its reverse (12049313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31394021 - 2² = 31394017 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31394221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15697010 + 15697011.

It is an arithmetic number, because the mean of its divisors is an integer number (15697011).

Almost surely, 2^31394021 is an apocalyptic number.

It is an amenable number.

31394021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31394021 is an equidigital number, since it uses as much as digits as its factorization.

31394021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 31394021 is about 5603.0367658976. The cubic root of 31394021 is about 315.4634012614.

The spelling of 31394021 in words is "thirty-one million, three hundred ninety-four thousand, twenty-one".