81490697 has 2 divisors, whose sum is σ = 81490698. Its totient is φ = 81490696.

The previous prime is 81490681. The next prime is 81490729. The reversal of 81490697 is 79609418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60155536 + 21335161 = 7756^2 + 4619^2 .

It is a cyclic number.

It is not a de Polignac number, because 81490697 - 2⁴ = 81490681 is a prime.

It is not a weakly prime, because it can be changed into another prime (81490637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40745348 + 40745349.

It is an arithmetic number, because the mean of its divisors is an integer number (40745349).

Almost surely, 2^81490697 is an apocalyptic number.

It is an amenable number.

81490697 is a deficient number, since it is larger than the sum of its proper divisors (1).

81490697 is an equidigital number, since it uses as much as digits as its factorization.

81490697 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 81490697 is about 9027.2197824136. The cubic root of 81490697 is about 433.5468257012.

The spelling of 81490697 in words is "eighty-one million, four hundred ninety thousand, six hundred ninety-seven".