78295925921 has 2 divisors, whose sum is σ = 78295925922. Its totient is φ = 78295925920.

The previous prime is 78295925881. The next prime is 78295925927. The reversal of 78295925921 is 12952959287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64650181696 + 13645744225 = 254264^2 + 116815^2 .

It is an emirp because it is prime and its reverse (12952959287) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78295925921 - 2³⁰ = 77222184097 is a prime.

It is a super-2 number, since 2×78295925921² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78295925927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39147962960 + 39147962961.

It is an arithmetic number, because the mean of its divisors is an integer number (39147962961).

Almost surely, 2^78295925921 is an apocalyptic number.

It is an amenable number.

78295925921 is a deficient number, since it is larger than the sum of its proper divisors (1).

78295925921 is an equidigital number, since it uses as much as digits as its factorization.

78295925921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8164800, while the sum is 59.

The spelling of 78295925921 in words is "seventy-eight billion, two hundred ninety-five million, nine hundred twenty-five thousand, nine hundred twenty-one".