79221378721 has 2 divisors, whose sum is σ = 79221378722. Its totient is φ = 79221378720.

The previous prime is 79221378713. The next prime is 79221378737. The reversal of 79221378721 is 12787312297.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 67652010000 + 11569368721 = 260100^2 + 107561^2 .

It is a cyclic number.

It is not a de Polignac number, because 79221378721 - 2³ = 79221378713 is a prime.

It is a super-2 number, since 2×79221378721² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (79221378221) 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, 39610689360 + 39610689361.

It is an arithmetic number, because the mean of its divisors is an integer number (39610689361).

Almost surely, 2^79221378721 is an apocalyptic number.

It is an amenable number.

79221378721 is a deficient number, since it is larger than the sum of its proper divisors (1).

79221378721 is an equidigital number, since it uses as much as digits as its factorization.

79221378721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 592704, while the sum is 49.

The spelling of 79221378721 in words is "seventy-nine billion, two hundred twenty-one million, three hundred seventy-eight thousand, seven hundred twenty-one".