80721779029 has 2 divisors, whose sum is σ = 80721779030. Its totient is φ = 80721779028.

The previous prime is 80721779023. The next prime is 80721779057. The reversal of 80721779029 is 92097712708.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71433252900 + 9288526129 = 267270^2 + 96377^2 .

It is a cyclic number.

It is not a de Polignac number, because 80721779029 - 2³¹ = 78574295381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80721779023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40360889514 + 40360889515.

It is an arithmetic number, because the mean of its divisors is an integer number (40360889515).

Almost surely, 2^80721779029 is an apocalyptic number.

It is an amenable number.

80721779029 is a deficient number, since it is larger than the sum of its proper divisors (1).

80721779029 is an equidigital number, since it uses as much as digits as its factorization.

80721779029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 889056, while the sum is 52.

The spelling of 80721779029 in words is "eighty billion, seven hundred twenty-one million, seven hundred seventy-nine thousand, twenty-nine".