21091367668 has 48 divisors (see below), whose sum is σ = 43345572480. Its totient is φ = 8790235776.

The previous prime is 21091367663. The next prime is 21091367681. The reversal of 21091367668 is 86676319012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21091367663) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2562063 + ... + 2570281.

It is an arithmetic number, because the mean of its divisors is an integer number (903032760).

Almost surely, 2^21091367668 is an apocalyptic number.

21091367668 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21091367668 is an abundant number, since it is smaller than the sum of its proper divisors (22254204812).

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

21091367668 is a wasteful number, since it uses less digits than its factorization.

21091367668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10744 (or 10742 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 49.

The spelling of 21091367668 in words is "twenty-one billion, ninety-one million, three hundred sixty-seven thousand, six hundred sixty-eight".