78222021121 has 2 divisors, whose sum is σ = 78222021122. Its totient is φ = 78222021120.

The previous prime is 78222021113. The next prime is 78222021167. The reversal of 78222021121 is 12112022287.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77765130496 + 456890625 = 278864^2 + 21375^2 .

It is an emirp because it is prime and its reverse (12112022287) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78222021121 - 2³ = 78222021113 is a prime.

It is a super-2 number, since 2×78222021121² (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 78222021121.

It is not a weakly prime, because it can be changed into another prime (78222021221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39111010560 + 39111010561.

It is an arithmetic number, because the mean of its divisors is an integer number (39111010561).

Almost surely, 2^78222021121 is an apocalyptic number.

It is an amenable number.

78222021121 is a deficient number, since it is larger than the sum of its proper divisors (1).

78222021121 is an equidigital number, since it uses as much as digits as its factorization.

78222021121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1792, while the sum is 28.

The spelling of 78222021121 in words is "seventy-eight billion, two hundred twenty-two million, twenty-one thousand, one hundred twenty-one".