81219801599 has 2 divisors, whose sum is σ = 81219801600. Its totient is φ = 81219801598.

The previous prime is 81219801587. The next prime is 81219801653. The reversal of 81219801599 is 99510891218.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81219801599 - 2²⁸ = 80951366143 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81219801599.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81219851599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40609900799 + 40609900800.

It is an arithmetic number, because the mean of its divisors is an integer number (40609900800).

Almost surely, 2^81219801599 is an apocalyptic number.

81219801599 is a deficient number, since it is larger than the sum of its proper divisors (1).

81219801599 is an equidigital number, since it uses as much as digits as its factorization.

81219801599 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 466560, while the sum is 53.

The spelling of 81219801599 in words is "eighty-one billion, two hundred nineteen million, eight hundred one thousand, five hundred ninety-nine".