79921018889 has 2 divisors, whose sum is σ = 79921018890. Its totient is φ = 79921018888.

The previous prime is 79921018883. The next prime is 79921018951. The reversal of 79921018889 is 98881012997.

It is a happy number.

It is an a-pointer prime, because the next prime (79921018951) can be obtained adding 79921018889 to its sum of digits (62).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67916529664 + 12004489225 = 260608^2 + 109565^2 .

It is a cyclic number.

It is not a de Polignac number, because 79921018889 - 2¹⁶ = 79920953353 is a prime.

It is not a weakly prime, because it can be changed into another prime (79921018883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39960509444 + 39960509445.

It is an arithmetic number, because the mean of its divisors is an integer number (39960509445).

Almost surely, 2^79921018889 is an apocalyptic number.

It is an amenable number.

79921018889 is a deficient number, since it is larger than the sum of its proper divisors (1).

79921018889 is an equidigital number, since it uses as much as digits as its factorization.

79921018889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5225472, while the sum is 62.

The spelling of 79921018889 in words is "seventy-nine billion, nine hundred twenty-one million, eighteen thousand, eight hundred eighty-nine".