21366680 has 16 divisors (see below), whose sum is σ = 48075120. Its totient is φ = 8546656.

The previous prime is 21366679. The next prime is 21366689. The reversal of 21366680 is 8666312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21366689) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 267044 + ... + 267123.

It is an arithmetic number, because the mean of its divisors is an integer number (3004695).

Almost surely, 2^21366680 is an apocalyptic number.

21366680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21366680 is an abundant number, since it is smaller than the sum of its proper divisors (26708440).

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

21366680 is a wasteful number, since it uses less digits than its factorization.

21366680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 534178 (or 534174 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 32.

The square root of 21366680 is about 4622.4106265022. The cubic root of 21366680 is about 277.4889425565.

The spelling of 21366680 in words is "twenty-one million, three hundred sixty-six thousand, six hundred eighty".