31443521 has 2 divisors, whose sum is σ = 31443522. Its totient is φ = 31443520.

The previous prime is 31443481. The next prime is 31443551. The reversal of 31443521 is 12534413.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 31360000 + 83521 = 5600^2 + 289^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31443521 is a prime.

It is not a weakly prime, because it can be changed into another prime (31443551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15721760 + 15721761.

It is an arithmetic number, because the mean of its divisors is an integer number (15721761).

Almost surely, 2^31443521 is an apocalyptic number.

It is an amenable number.

31443521 is a deficient number, since it is larger than the sum of its proper divisors (1).

31443521 is an equidigital number, since it uses as much as digits as its factorization.

31443521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 23.

The square root of 31443521 is about 5607.4522735374. The cubic root of 31443521 is about 315.6291147521.

Adding to 31443521 its reverse (12534413), we get a palindrome (43977934).

The spelling of 31443521 in words is "thirty-one million, four hundred forty-three thousand, five hundred twenty-one".