31020421 has 4 divisors (see below), whose sum is σ = 31295052. Its totient is φ = 30745792.

The previous prime is 31020373. The next prime is 31020449. The reversal of 31020421 is 12402013.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12402013 = 13 ⋅954001.

It can be written as a sum of positive squares in 2 ways, for example, as 2280100 + 28740321 = 1510^2 + 5361^2 .

It is a cyclic number.

It is not a de Polignac number, because 31020421 - 2⁹ = 31019909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31020481) 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 in 3 ways as a sum of consecutive naturals, for example, 137146 + ... + 137371.

It is an arithmetic number, because the mean of its divisors is an integer number (7823763).

Almost surely, 2^31020421 is an apocalyptic number.

It is an amenable number.

31020421 is a deficient number, since it is larger than the sum of its proper divisors (274631).

31020421 is a wasteful number, since it uses less digits than its factorization.

31020421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274630.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 31020421 is about 5569.5979208557. The cubic root of 31020421 is about 314.2070287373.

Adding to 31020421 its reverse (12402013), we get a palindrome (43422434).

The spelling of 31020421 in words is "thirty-one million, twenty thousand, four hundred twenty-one".