81290917 has 4 divisors (see below), whose sum is σ = 81309600. Its totient is φ = 81272236.

The previous prime is 81290893. The next prime is 81290927. The reversal of 81290917 is 71909218.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81290917 - 2¹⁹ = 80766629 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81290927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1008 + ... + 12790.

It is an arithmetic number, because the mean of its divisors is an integer number (20327400).

Almost surely, 2^81290917 is an apocalyptic number.

It is an amenable number.

81290917 is a deficient number, since it is larger than the sum of its proper divisors (18683).

81290917 is a wasteful number, since it uses less digits than its factorization.

81290917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18682.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 81290917 is about 9016.1475697772. The cubic root of 81290917 is about 433.1922459163.

The spelling of 81290917 in words is "eighty-one million, two hundred ninety thousand, nine hundred seventeen".