78403753783921 has 2 divisors, whose sum is σ = 78403753783922. Its totient is φ = 78403753783920.

The previous prime is 78403753783907. The next prime is 78403753783963. The reversal of 78403753783921 is 12938735730487.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62851772823921 + 15551980960000 = 7927911^2 + 3943600^2 .

It is a cyclic number.

It is not a de Polignac number, because 78403753783921 - 2²⁵ = 78403720229489 is a prime.

It is a super-2 number, since 2×78403753783921² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78403753783991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39201876891960 + 39201876891961.

It is an arithmetic number, because the mean of its divisors is an integer number (39201876891961).

Almost surely, 2^{78403753783921} is an apocalyptic number.

It is an amenable number.

78403753783921 is a deficient number, since it is larger than the sum of its proper divisors (1).

78403753783921 is an equidigital number, since it uses as much as digits as its factorization.

78403753783921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 213373440, while the sum is 67.

The spelling of 78403753783921 in words is "seventy-eight trillion, four hundred three billion, seven hundred fifty-three million, seven hundred eighty-three thousand, nine hundred twenty-one".