81099643 has 2 divisors, whose sum is σ = 81099644. Its totient is φ = 81099642.

The previous prime is 81099637. The next prime is 81099653. The reversal of 81099643 is 34699018.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81099643 - 2¹⁷ = 80968571 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81099596 and 81099605.

It is not a weakly prime, because it can be changed into another prime (81099653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40549821 + 40549822.

It is an arithmetic number, because the mean of its divisors is an integer number (40549822).

Almost surely, 2^81099643 is an apocalyptic number.

81099643 is a deficient number, since it is larger than the sum of its proper divisors (1).

81099643 is an equidigital number, since it uses as much as digits as its factorization.

81099643 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 81099643 is about 9005.5340208119. The cubic root of 81099643 is about 432.8522182346.

The spelling of 81099643 in words is "eighty-one million, ninety-nine thousand, six hundred forty-three".