31860421 has 2 divisors, whose sum is σ = 31860422. Its totient is φ = 31860420.

The previous prime is 31860401. The next prime is 31860449. The reversal of 31860421 is 12406813.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 11655396 = 4495^2 + 3414^2 .

It is an emirp because it is prime and its reverse (12406813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31860421 - 2¹¹ = 31858373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31860401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15930210 + 15930211.

It is an arithmetic number, because the mean of its divisors is an integer number (15930211).

Almost surely, 2^31860421 is an apocalyptic number.

It is an amenable number.

31860421 is a deficient number, since it is larger than the sum of its proper divisors (1).

31860421 is an equidigital number, since it uses as much as digits as its factorization.

31860421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 31860421 is about 5644.5036097074. The cubic root of 31860421 is about 317.0179379302.

The spelling of 31860421 in words is "thirty-one million, eight hundred sixty thousand, four hundred twenty-one".