81365474479 has 2 divisors, whose sum is σ = 81365474480. Its totient is φ = 81365474478.

The previous prime is 81365474473. The next prime is 81365474573. The reversal of 81365474479 is 97447456318.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81365474479 - 2²³ = 81357085871 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81365474473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40682737239 + 40682737240.

It is an arithmetic number, because the mean of its divisors is an integer number (40682737240).

Almost surely, 2^81365474479 is an apocalyptic number.

81365474479 is a deficient number, since it is larger than the sum of its proper divisors (1).

81365474479 is an equidigital number, since it uses as much as digits as its factorization.

81365474479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20321280, while the sum is 58.

The spelling of 81365474479 in words is "eighty-one billion, three hundred sixty-five million, four hundred seventy-four thousand, four hundred seventy-nine".