31445681 has 2 divisors, whose sum is σ = 31445682. Its totient is φ = 31445680.

The previous prime is 31445677. The next prime is 31445693. The reversal of 31445681 is 18654413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21077281 + 10368400 = 4591^2 + 3220^2 .

It is a cyclic number.

It is not a de Polignac number, because 31445681 - 2² = 31445677 is a prime.

It is a super-2 number, since 2×31445681² = 1977661707107522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31445611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15722840 + 15722841.

It is an arithmetic number, because the mean of its divisors is an integer number (15722841).

Almost surely, 2^31445681 is an apocalyptic number.

It is an amenable number.

31445681 is a deficient number, since it is larger than the sum of its proper divisors (1).

31445681 is an equidigital number, since it uses as much as digits as its factorization.

31445681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11520, while the sum is 32.

The square root of 31445681 is about 5607.6448710666. The cubic root of 31445681 is about 315.6363419249.

The spelling of 31445681 in words is "thirty-one million, four hundred forty-five thousand, six hundred eighty-one".