31008421 has 2 divisors, whose sum is σ = 31008422. Its totient is φ = 31008420.

The previous prime is 31008413. The next prime is 31008431. The reversal of 31008421 is 12480013.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25391521 + 5616900 = 5039^2 + 2370^2 .

It is a cyclic number.

It is not a de Polignac number, because 31008421 - 2³ = 31008413 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31008431) 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, 15504210 + 15504211.

It is an arithmetic number, because the mean of its divisors is an integer number (15504211).

Almost surely, 2^31008421 is an apocalyptic number.

It is an amenable number.

31008421 is a deficient number, since it is larger than the sum of its proper divisors (1).

31008421 is an equidigital number, since it uses as much as digits as its factorization.

31008421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 31008421 is about 5568.5205396048. The cubic root of 31008421 is about 314.1665073590.

Adding to 31008421 its reverse (12480013), we get a palindrome (43488434).

The spelling of 31008421 in words is "thirty-one million, eight thousand, four hundred twenty-one".