81422989 has 2 divisors, whose sum is σ = 81422990. Its totient is φ = 81422988.

The previous prime is 81422963. The next prime is 81422993. The reversal of 81422989 is 98922418.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 80245764 + 1177225 = 8958^2 + 1085^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81422989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81422389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40711494 + 40711495.

It is an arithmetic number, because the mean of its divisors is an integer number (40711495).

Almost surely, 2^81422989 is an apocalyptic number.

It is an amenable number.

81422989 is a deficient number, since it is larger than the sum of its proper divisors (1).

81422989 is an equidigital number, since it uses as much as digits as its factorization.

81422989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 43.

The square root of 81422989 is about 9023.4687897726. The cubic root of 81422989 is about 433.4267190582.

The spelling of 81422989 in words is "eighty-one million, four hundred twenty-two thousand, nine hundred eighty-nine".