31824421 has 2 divisors, whose sum is σ = 31824422. Its totient is φ = 31824420.

The previous prime is 31824413. The next prime is 31824431. The reversal of 31824421 is 12442813.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21520321 + 10304100 = 4639^2 + 3210^2 .

It is an emirp because it is prime and its reverse (12442813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31824421 - 2³ = 31824413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31824431) 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, 15912210 + 15912211.

It is an arithmetic number, because the mean of its divisors is an integer number (15912211).

Almost surely, 2^31824421 is an apocalyptic number.

It is an amenable number.

31824421 is a deficient number, since it is larger than the sum of its proper divisors (1).

31824421 is an equidigital number, since it uses as much as digits as its factorization.

31824421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1536, while the sum is 25.

The square root of 31824421 is about 5641.3137654273. The cubic root of 31824421 is about 316.8984903878.

The spelling of 31824421 in words is "thirty-one million, eight hundred twenty-four thousand, four hundred twenty-one".