63121819891 has 16 divisors (see below), whose sum is σ = 70571763360. Its totient is φ = 56056815360.

The previous prime is 63121819889. The next prime is 63121819933. The reversal of 63121819891 is 19891812136.

It is not a de Polignac number, because 63121819891 - 2¹ = 63121819889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (63121819801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 191985 + ... + 403858.

It is an arithmetic number, because the mean of its divisors is an integer number (4410735210).

Almost surely, 2^63121819891 is an apocalyptic number.

63121819891 is a deficient number, since it is larger than the sum of its proper divisors (7449943469).

63121819891 is a wasteful number, since it uses less digits than its factorization.

63121819891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 596166.

The product of its digits is 186624, while the sum is 49.

The spelling of 63121819891 in words is "sixty-three billion, one hundred twenty-one million, eight hundred nineteen thousand, eight hundred ninety-one".