31222981 has 2 divisors, whose sum is σ = 31222982. Its totient is φ = 31222980.

The previous prime is 31222973. The next prime is 31222987. The reversal of 31222981 is 18922213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 30636225 + 586756 = 5535^2 + 766^2 .

It is a cyclic number.

It is not a de Polignac number, because 31222981 - 2³ = 31222973 is a prime.

It is a super-2 number, since 2×31222981² = 1949749085052722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31222987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15611490 + 15611491.

It is an arithmetic number, because the mean of its divisors is an integer number (15611491).

Almost surely, 2^31222981 is an apocalyptic number.

It is an amenable number.

31222981 is a deficient number, since it is larger than the sum of its proper divisors (1).

31222981 is an equidigital number, since it uses as much as digits as its factorization.

31222981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 28.

The square root of 31222981 is about 5587.7527683318. The cubic root of 31222981 is about 314.8894581470.

The spelling of 31222981 in words is "thirty-one million, two hundred twenty-two thousand, nine hundred eighty-one".