31909481 has 2 divisors, whose sum is σ = 31909482. Its totient is φ = 31909480.

The previous prime is 31909463. The next prime is 31909499. The reversal of 31909481 is 18490913.

It is a balanced prime because it is at equal distance from previous prime (31909463) and next prime (31909499).

It can be written as a sum of positive squares in only one way, i.e., 26173456 + 5736025 = 5116^2 + 2395^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31909481 is a prime.

It is a super-2 number, since 2×31909481² = 2036429955378722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31909421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15954740 + 15954741.

It is an arithmetic number, because the mean of its divisors is an integer number (15954741).

Almost surely, 2^31909481 is an apocalyptic number.

It is an amenable number.

31909481 is a deficient number, since it is larger than the sum of its proper divisors (1).

31909481 is an equidigital number, since it uses as much as digits as its factorization.

31909481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 31909481 is about 5648.8477586141. The cubic root of 31909481 is about 317.1805736118.

The spelling of 31909481 in words is "thirty-one million, nine hundred nine thousand, four hundred eighty-one".