81928997 has 2 divisors, whose sum is σ = 81928998. Its totient is φ = 81928996.

The previous prime is 81928949. The next prime is 81929009. The reversal of 81928997 is 79982918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 79103236 + 2825761 = 8894^2 + 1681^2 .

It is a cyclic number.

It is not a de Polignac number, because 81928997 - 2¹⁸ = 81666853 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81928927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40964498 + 40964499.

It is an arithmetic number, because the mean of its divisors is an integer number (40964499).

Almost surely, 2^81928997 is an apocalyptic number.

It is an amenable number.

81928997 is a deficient number, since it is larger than the sum of its proper divisors (1).

81928997 is an equidigital number, since it uses as much as digits as its factorization.

81928997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 653184, while the sum is 53.

The square root of 81928997 is about 9051.4638042695. The cubic root of 81928997 is about 434.3227175623.

The spelling of 81928997 in words is "eighty-one million, nine hundred twenty-eight thousand, nine hundred ninety-seven".