79801165421 has 2 divisors, whose sum is σ = 79801165422. Its totient is φ = 79801165420.

The previous prime is 79801165399. The next prime is 79801165429. The reversal of 79801165421 is 12456110897.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51295908196 + 28505257225 = 226486^2 + 168835^2 .

It is a cyclic number.

It is not a de Polignac number, because 79801165421 - 2¹⁴ = 79801149037 is a prime.

It is a super-2 number, since 2×79801165421² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79801165429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39900582710 + 39900582711.

It is an arithmetic number, because the mean of its divisors is an integer number (39900582711).

Almost surely, 2^79801165421 is an apocalyptic number.

It is an amenable number.

79801165421 is a deficient number, since it is larger than the sum of its proper divisors (1).

79801165421 is an equidigital number, since it uses as much as digits as its factorization.

79801165421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120960, while the sum is 44.

The spelling of 79801165421 in words is "seventy-nine billion, eight hundred one million, one hundred sixty-five thousand, four hundred twenty-one".