21266680 has 16 divisors (see below), whose sum is σ = 47850120. Its totient is φ = 8506656.

The previous prime is 21266669. The next prime is 21266731. The reversal of 21266680 is 8666212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 265794 + ... + 265873.

Almost surely, 2^21266680 is an apocalyptic number.

21266680 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21266680 is an abundant number, since it is smaller than the sum of its proper divisors (26583440).

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

21266680 is a wasteful number, since it uses less digits than its factorization.

21266680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 531678 (or 531674 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 21266680 is about 4611.5810737750. The cubic root of 21266680 is about 277.0553656485.

The spelling of 21266680 in words is "twenty-one million, two hundred sixty-six thousand, six hundred eighty".