31427989 has 2 divisors, whose sum is σ = 31427990. Its totient is φ = 31427988.

The previous prime is 31427987. The next prime is 31428013. The reversal of 31427989 is 98972413.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19580625 + 11847364 = 4425^2 + 3442^2 .

It is a cyclic number.

It is not a de Polignac number, because 31427989 - 2¹ = 31427987 is a prime.

Together with 31427987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31427983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15713994 + 15713995.

It is an arithmetic number, because the mean of its divisors is an integer number (15713995).

Almost surely, 2^31427989 is an apocalyptic number.

It is an amenable number.

31427989 is a deficient number, since it is larger than the sum of its proper divisors (1).

31427989 is an equidigital number, since it uses as much as digits as its factorization.

31427989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 43.

The square root of 31427989 is about 5606.0671597832. The cubic root of 31427989 is about 315.5771362769.

The spelling of 31427989 in words is "thirty-one million, four hundred twenty-seven thousand, nine hundred eighty-nine".