22615981 has 2 divisors, whose sum is σ = 22615982. Its totient is φ = 22615980.

The previous prime is 22615961. The next prime is 22615987. The reversal of 22615981 is 18951622.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14402025 + 8213956 = 3795^2 + 2866^2 .

It is a cyclic number.

It is not a de Polignac number, because 22615981 - 2¹⁷ = 22484909 is a prime.

It is a super-2 number, since 2×22615981² = 1022965193184722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22615987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11307990 + 11307991.

It is an arithmetic number, because the mean of its divisors is an integer number (11307991).

Almost surely, 2^22615981 is an apocalyptic number.

It is an amenable number.

22615981 is a deficient number, since it is larger than the sum of its proper divisors (1).

22615981 is an equidigital number, since it uses as much as digits as its factorization.

22615981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 34.

The square root of 22615981 is about 4755.6262468785. The cubic root of 22615981 is about 282.7950544533.

The spelling of 22615981 in words is "twenty-two million, six hundred fifteen thousand, nine hundred eighty-one".