79748640221 has 2 divisors, whose sum is σ = 79748640222. Its totient is φ = 79748640220.

The previous prime is 79748640217. The next prime is 79748640233. The reversal of 79748640221 is 12204684797.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56519832121 + 23228808100 = 237739^2 + 152410^2 .

It is a cyclic number.

It is not a de Polignac number, because 79748640221 - 2² = 79748640217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 79748640221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (79748660221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39874320110 + 39874320111.

It is an arithmetic number, because the mean of its divisors is an integer number (39874320111).

Almost surely, 2^79748640221 is an apocalyptic number.

It is an amenable number.

79748640221 is a deficient number, since it is larger than the sum of its proper divisors (1).

79748640221 is an equidigital number, since it uses as much as digits as its factorization.

79748640221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1354752, while the sum is 50.

The spelling of 79748640221 in words is "seventy-nine billion, seven hundred forty-eight million, six hundred forty thousand, two hundred twenty-one".