31343561 has 2 divisors, whose sum is σ = 31343562. Its totient is φ = 31343560.

The previous prime is 31343537. The next prime is 31343567. The reversal of 31343561 is 16534313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 26419600 + 4923961 = 5140^2 + 2219^2 .

It is a cyclic number.

It is not a de Polignac number, because 31343561 - 2⁶ = 31343497 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31343561.

It is not a weakly prime, because it can be changed into another prime (31343567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15671780 + 15671781.

It is an arithmetic number, because the mean of its divisors is an integer number (15671781).

Almost surely, 2^31343561 is an apocalyptic number.

It is an amenable number.

31343561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31343561 is an equidigital number, since it uses as much as digits as its factorization.

31343561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 26.

The square root of 31343561 is about 5598.5320397404. The cubic root of 31343561 is about 315.2942945452.

Adding to 31343561 its reverse (16534313), we get a palindrome (47877874).

The spelling of 31343561 in words is "thirty-one million, three hundred forty-three thousand, five hundred sixty-one".