21267730 has 64 divisors (see below), whose sum is σ = 44323200. Its totient is φ = 7275520.

The previous prime is 21267721. The next prime is 21267737. The reversal of 21267730 is 3776212.

It is not an unprimeable number, because it can be changed into a prime (21267737) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 188154 + ... + 188266.

It is an arithmetic number, because the mean of its divisors is an integer number (692550).

Almost surely, 2^21267730 is an apocalyptic number.

21267730 is an abundant number, since it is smaller than the sum of its proper divisors (23055470).

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

21267730 is a wasteful number, since it uses less digits than its factorization.

21267730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219.

The product of its (nonzero) digits is 3528, while the sum is 28.

The square root of 21267730 is about 4611.6949161886. The cubic root of 21267730 is about 277.0599252592.

The spelling of 21267730 in words is "twenty-one million, two hundred sixty-seven thousand, seven hundred thirty".