78789226921 has 2 divisors, whose sum is σ = 78789226922. Its totient is φ = 78789226920.

The previous prime is 78789226877. The next prime is 78789226927. The reversal of 78789226921 is 12962298787.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78756003225 + 33223696 = 280635^2 + 5764^2 .

It is a cyclic number.

It is not a de Polignac number, because 78789226921 - 2¹¹ = 78789224873 is a prime.

It is a super-2 number, since 2×78789226921² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 78789226921.

It is not a weakly prime, because it can be changed into another prime (78789226927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39394613460 + 39394613461.

It is an arithmetic number, because the mean of its divisors is an integer number (39394613461).

Almost surely, 2^78789226921 is an apocalyptic number.

It is an amenable number.

78789226921 is a deficient number, since it is larger than the sum of its proper divisors (1).

78789226921 is an equidigital number, since it uses as much as digits as its factorization.

78789226921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12192768, while the sum is 61.

The spelling of 78789226921 in words is "seventy-eight billion, seven hundred eighty-nine million, two hundred twenty-six thousand, nine hundred twenty-one".