81490369 has 2 divisors, whose sum is σ = 81490370. Its totient is φ = 81490368.

The previous prime is 81490349. The next prime is 81490393. The reversal of 81490369 is 96309418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52200625 + 29289744 = 7225^2 + 5412^2 .

It is a cyclic number.

It is not a de Polignac number, because 81490369 - 2¹⁵ = 81457601 is a prime.

It is a super-2 number, since 2×81490369² = 13281360479512322, which contains 22 as substring.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is not a weakly prime, because it can be changed into another prime (81490349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40745184 + 40745185.

It is an arithmetic number, because the mean of its divisors is an integer number (40745185).

Almost surely, 2^81490369 is an apocalyptic number.

It is an amenable number.

81490369 is a deficient number, since it is larger than the sum of its proper divisors (1).

81490369 is an equidigital number, since it uses as much as digits as its factorization.

81490369 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 81490369 is about 9027.2016151186. The cubic root of 81490369 is about 433.5462440252.

The spelling of 81490369 in words is "eighty-one million, four hundred ninety thousand, three hundred sixty-nine".