21655212501079 has 2 divisors, whose sum is σ = 21655212501080. Its totient is φ = 21655212501078.

The previous prime is 21655212501071. The next prime is 21655212501149. The reversal of 21655212501079 is 97010521255612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21655212501079 - 2³ = 21655212501071 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21655212501071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10827606250539 + 10827606250540.

It is an arithmetic number, because the mean of its divisors is an integer number (10827606250540).

Almost surely, 2^{21655212501079} is an apocalyptic number.

21655212501079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21655212501079 is an equidigital number, since it uses as much as digits as its factorization.

21655212501079 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 378000, while the sum is 46.

The spelling of 21655212501079 in words is "twenty-one trillion, six hundred fifty-five billion, two hundred twelve million, five hundred one thousand, seventy-nine".