31244021 has 4 divisors (see below), whose sum is σ = 32088492. Its totient is φ = 30399552.

The previous prime is 31243967. The next prime is 31244077. The reversal of 31244021 is 12044213.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21252100 + 9991921 = 4610^2 + 3161^2 .

It is a cyclic number.

It is not a de Polignac number, because 31244021 - 2⁶ = 31243957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31244221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 422180 + ... + 422253.

It is an arithmetic number, because the mean of its divisors is an integer number (8022123).

Almost surely, 2^31244021 is an apocalyptic number.

It is an amenable number.

31244021 is a deficient number, since it is larger than the sum of its proper divisors (844471).

31244021 is an equidigital number, since it uses as much as digits as its factorization.

31244021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 844470.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 31244021 is about 5589.6351401500. The cubic root of 31244021 is about 314.9601730112.

Adding to 31244021 its product of nonzero digits (192), we get a palindrome (31244213).

Adding to 31244021 its reverse (12044213), we get a palindrome (43288234).

The spelling of 31244021 in words is "thirty-one million, two hundred forty-four thousand, twenty-one".