21574777681 has 16 divisors (see below), whose sum is σ = 22464864000. Its totient is φ = 20703200128.

The previous prime is 21574777643. The next prime is 21574777711. The reversal of 21574777681 is 18677747512.

It is a cyclic number.

It is not a de Polignac number, because 21574777681 - 2¹⁵ = 21574744913 is a prime.

It is a super-2 number, since 2×21574777681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21574777181) 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, 6721605 + ... + 6724813.

It is an arithmetic number, because the mean of its divisors is an integer number (1404054000).

Almost surely, 2^21574777681 is an apocalyptic number.

It is an amenable number.

21574777681 is a deficient number, since it is larger than the sum of its proper divisors (890086319).

21574777681 is a wasteful number, since it uses less digits than its factorization.

21574777681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6008.

The product of its digits is 4609920, while the sum is 55.

The spelling of 21574777681 in words is "twenty-one billion, five hundred seventy-four million, seven hundred seventy-seven thousand, six hundred eighty-one".