31544021 has 2 divisors, whose sum is σ = 31544022. Its totient is φ = 31544020.

The previous prime is 31544011. The next prime is 31544033. The reversal of 31544021 is 12044513.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16443025 + 15100996 = 4055^2 + 3886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31544021 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 31543984 and 31544002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31544011) 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, 15772010 + 15772011.

It is an arithmetic number, because the mean of its divisors is an integer number (15772011).

Almost surely, 2^31544021 is an apocalyptic number.

It is an amenable number.

31544021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31544021 is an equidigital number, since it uses as much as digits as its factorization.

31544021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 31544021 is about 5616.4064133572. The cubic root of 31544021 is about 315.9650291108.

Adding to 31544021 its reverse (12044513), we get a palindrome (43588534).

The spelling of 31544021 in words is "thirty-one million, five hundred forty-four thousand, twenty-one".