21266830 has 32 divisors (see below), whose sum is σ = 43654464. Its totient is φ = 7389696.

The previous prime is 21266807. The next prime is 21266849. The reversal of 21266830 is 3866212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2602 + ... + 7021.

It is an arithmetic number, because the mean of its divisors is an integer number (1364202).

Almost surely, 2^21266830 is an apocalyptic number.

21266830 is an abundant number, since it is smaller than the sum of its proper divisors (22387634).

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

21266830 is a wasteful number, since it uses less digits than its factorization.

21266830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9660.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 21266830 is about 4611.5973371490. The cubic root of 21266830 is about 277.0560170306.

The spelling of 21266830 in words is "twenty-one million, two hundred sixty-six thousand, eight hundred thirty".