63193781921 has 2 divisors, whose sum is σ = 63193781922. Its totient is φ = 63193781920.

The previous prime is 63193781881. The next prime is 63193781923. The reversal of 63193781921 is 12918739136.

63193781921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61585370896 + 1608411025 = 248164^2 + 40105^2 .

It is a cyclic number.

It is not a de Polignac number, because 63193781921 - 2³⁰ = 62120040097 is a prime.

Together with 63193781923, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 63193781921.

It is not a weakly prime, because it can be changed into another prime (63193781923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31596890960 + 31596890961.

It is an arithmetic number, because the mean of its divisors is an integer number (31596890961).

Almost surely, 2^63193781921 is an apocalyptic number.

It is an amenable number.

63193781921 is a deficient number, since it is larger than the sum of its proper divisors (1).

63193781921 is an equidigital number, since it uses as much as digits as its factorization.

63193781921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 50.

The spelling of 63193781921 in words is "sixty-three billion, one hundred ninety-three million, seven hundred eighty-one thousand, nine hundred twenty-one".