79145221 has 4 divisors (see below), whose sum is σ = 79242444. Its totient is φ = 79048000.

The previous prime is 79145219. The next prime is 79145237. The reversal of 79145221 is 12254197.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6708100 + 72437121 = 2590^2 + 8511^2 .

It is a cyclic number.

It is not a de Polignac number, because 79145221 - 2¹ = 79145219 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79145021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47380 + ... + 49021.

It is an arithmetic number, because the mean of its divisors is an integer number (19810611).

Almost surely, 2^79145221 is an apocalyptic number.

It is an amenable number.

79145221 is a deficient number, since it is larger than the sum of its proper divisors (97223).

79145221 is an equidigital number, since it uses as much as digits as its factorization.

79145221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97222.

The product of its digits is 5040, while the sum is 31.

The square root of 79145221 is about 8896.3599859718. The cubic root of 79145221 is about 429.3468016529.

The spelling of 79145221 in words is "seventy-nine million, one hundred forty-five thousand, two hundred twenty-one".