31300021 has 2 divisors, whose sum is σ = 31300022. Its totient is φ = 31300020.

The previous prime is 31300013. The next prime is 31300067. The reversal of 31300021 is 12000313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 26936100 + 4363921 = 5190^2 + 2089^2 .

It is a cyclic number.

It is not a de Polignac number, because 31300021 - 2³ = 31300013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31299980 and 31300007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31300081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15650010 + 15650011.

It is an arithmetic number, because the mean of its divisors is an integer number (15650011).

Almost surely, 2^31300021 is an apocalyptic number.

It is an amenable number.

31300021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31300021 is an equidigital number, since it uses as much as digits as its factorization.

31300021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 31300021 is about 5594.6421690757. The cubic root of 31300021 is about 315.1482329126.

Adding to 31300021 its reverse (12000313), we get a palindrome (43300334).

The spelling of 31300021 in words is "thirty-one million, three hundred thousand, twenty-one".