21042894 has 16 divisors (see below), whose sum is σ = 42140160. Its totient is φ = 7005240.

The previous prime is 21042883. The next prime is 21042911. The reversal of 21042894 is 49824012.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4177 + ... + 7715.

It is an arithmetic number, because the mean of its divisors is an integer number (2633760).

Almost surely, 2^21042894 is an apocalyptic number.

21042894 is an abundant number, since it is smaller than the sum of its proper divisors (21097266).

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

21042894 is a wasteful number, since it uses less digits than its factorization.

21042894 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4535.

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21042894 is about 4587.2534266160. The cubic root of 21042894 is about 276.0801332118.

The spelling of 21042894 in words is "twenty-one million, forty-two thousand, eight hundred ninety-four".