21487730 has 16 divisors (see below), whose sum is σ = 42194304. Its totient is φ = 7813680.

The previous prime is 21487717. The next prime is 21487751. The reversal of 21487730 is 3778412.

It is a happy number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97562 + ... + 97781.

It is an arithmetic number, because the mean of its divisors is an integer number (2637144).

Almost surely, 2^21487730 is an apocalyptic number.

21487730 is a deficient number, since it is larger than the sum of its proper divisors (20706574).

21487730 is a wasteful number, since it uses less digits than its factorization.

21487730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195361.

The product of its (nonzero) digits is 9408, while the sum is 32.

The square root of 21487730 is about 4635.4859507931. The cubic root of 21487730 is about 278.0119812651.

The spelling of 21487730 in words is "twenty-one million, four hundred eighty-seven thousand, seven hundred thirty".