21050111051720 has 64 divisors (see below), whose sum is σ = 50099013717120. Its totient is φ = 7943627349504.

The previous prime is 21050111051719. The next prime is 21050111051737. The reversal of 21050111051720 is 2715011105012.

It is a self number, because there is not a number n which added to its sum of digits gives 21050111051720.

It is an unprimeable number.

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, 156648974 + ... + 156783293.

It is an arithmetic number, because the mean of its divisors is an integer number (782797089330).

Almost surely, 2^{21050111051720} is an apocalyptic number.

21050111051720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21050111051720 is an abundant number, since it is smaller than the sum of its proper divisors (29048902665400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21050111051720 is a wasteful number, since it uses less digits than its factorization.

21050111051720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 313432374 (or 313432370 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 26.

Adding to 21050111051720 its reverse (2715011105012), we get a palindrome (23765122156732).

The spelling of 21050111051720 in words is "twenty-one trillion, fifty billion, one hundred eleven million, fifty-one thousand, seven hundred twenty".