21911835681 has 12 divisors (see below), whose sum is σ = 32169289620. Its totient is φ = 14368416480.

The previous prime is 21911835607. The next prime is 21911835691. The reversal of 21911835681 is 18653811912.

21911835681 is a `hidden beast` number, since 2 + 1 + 9 + 1 + 1 + 83 + 568 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1474560000 + 20437275681 = 38400^2 + 142959^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21911835681 is a prime.

It is a super-2 number, since 2×21911835681² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21911835691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19955586 + ... + 19956683.

It is an arithmetic number, because the mean of its divisors is an integer number (2680774135).

Almost surely, 2^21911835681 is an apocalyptic number.

It is an amenable number.

21911835681 is a deficient number, since it is larger than the sum of its proper divisors (10257453939).

21911835681 is a wasteful number, since it uses less digits than its factorization.

21911835681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39912336 (or 39912333 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The spelling of 21911835681 in words is "twenty-one billion, nine hundred eleven million, eight hundred thirty-five thousand, six hundred eighty-one".