21155056079 has 2 divisors, whose sum is σ = 21155056080. Its totient is φ = 21155056078.

The previous prime is 21155056073. The next prime is 21155056093. The reversal of 21155056079 is 97065055112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21155056079 - 2⁴ = 21155056063 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21155056073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10577528039 + 10577528040.

It is an arithmetic number, because the mean of its divisors is an integer number (10577528040).

Almost surely, 2^21155056079 is an apocalyptic number.

21155056079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21155056079 is an equidigital number, since it uses as much as digits as its factorization.

21155056079 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 94500, while the sum is 41.

The spelling of 21155056079 in words is "twenty-one billion, one hundred fifty-five million, fifty-six thousand, seventy-nine".