81235619 has 2 divisors, whose sum is σ = 81235620. Its totient is φ = 81235618.

The previous prime is 81235607. The next prime is 81235681. The reversal of 81235619 is 91653218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81235619 - 2²⁰ = 80187043 is a prime.

It is a super-2 number, since 2×81235619² = 13198451588626322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81235019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40617809 + 40617810.

It is an arithmetic number, because the mean of its divisors is an integer number (40617810).

Almost surely, 2^81235619 is an apocalyptic number.

81235619 is a deficient number, since it is larger than the sum of its proper divisors (1).

81235619 is an equidigital number, since it uses as much as digits as its factorization.

81235619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 35.

The square root of 81235619 is about 9013.0804390064. The cubic root of 81235619 is about 433.0939975533.

The spelling of 81235619 in words is "eighty-one million, two hundred thirty-five thousand, six hundred nineteen".