81231268619 has 2 divisors, whose sum is σ = 81231268620. Its totient is φ = 81231268618.

The previous prime is 81231268607. The next prime is 81231268621. The reversal of 81231268619 is 91686213218.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81231268619 - 2⁴ = 81231268603 is a prime.

It is a super-2 number, since 2×81231268619² (a number of 23 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 81231268621, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81231268639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40615634309 + 40615634310.

It is an arithmetic number, because the mean of its divisors is an integer number (40615634310).

Almost surely, 2^81231268619 is an apocalyptic number.

81231268619 is a deficient number, since it is larger than the sum of its proper divisors (1).

81231268619 is an equidigital number, since it uses as much as digits as its factorization.

81231268619 is an evil number, because the sum of its binary digits is even.

The product of its digits is 248832, while the sum is 47.

The spelling of 81231268619 in words is "eighty-one billion, two hundred thirty-one million, two hundred sixty-eight thousand, six hundred nineteen".