81421675591 has 2 divisors, whose sum is σ = 81421675592. Its totient is φ = 81421675590.

The previous prime is 81421675579. The next prime is 81421675603. The reversal of 81421675591 is 19557612418.

It is a balanced prime because it is at equal distance from previous prime (81421675579) and next prime (81421675603).

It is a cyclic number.

It is not a de Polignac number, because 81421675591 - 2⁹ = 81421675079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81421675091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40710837795 + 40710837796.

It is an arithmetic number, because the mean of its divisors is an integer number (40710837796).

Almost surely, 2^81421675591 is an apocalyptic number.

81421675591 is a deficient number, since it is larger than the sum of its proper divisors (1).

81421675591 is an equidigital number, since it uses as much as digits as its factorization.

81421675591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 604800, while the sum is 49.

The spelling of 81421675591 in words is "eighty-one billion, four hundred twenty-one million, six hundred seventy-five thousand, five hundred ninety-one".