21268085680 has 40 divisors (see below), whose sum is σ = 51043411584. Its totient is φ = 8232806400.

The previous prime is 21268085633. The next prime is 21268085681. The reversal of 21268085680 is 8658086212.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 21268085680.

It is not an unprimeable number, because it can be changed into a prime (21268085681) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4285441 + ... + 4290400.

Almost surely, 2^21268085680 is an apocalyptic number.

21268085680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21268085680 is an abundant number, since it is smaller than the sum of its proper divisors (29775325904).

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

21268085680 is a wasteful number, since it uses less digits than its factorization.

21268085680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8575885 (or 8575879 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 46.

The spelling of 21268085680 in words is "twenty-one billion, two hundred sixty-eight million, eighty-five thousand, six hundred eighty".