81421029659 has 2 divisors, whose sum is σ = 81421029660. Its totient is φ = 81421029658.

The previous prime is 81421029649. The next prime is 81421029673. The reversal of 81421029659 is 95692012418.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81421029659 is a prime.

It is not a weakly prime, because it can be changed into another prime (81421029629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40710514829 + 40710514830.

It is an arithmetic number, because the mean of its divisors is an integer number (40710514830).

Almost surely, 2^81421029659 is an apocalyptic number.

81421029659 is a deficient number, since it is larger than the sum of its proper divisors (1).

81421029659 is an equidigital number, since it uses as much as digits as its factorization.

81421029659 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 311040, while the sum is 47.

The spelling of 81421029659 in words is "eighty-one billion, four hundred twenty-one million, twenty-nine thousand, six hundred fifty-nine".