21045878 has 16 divisors (see below), whose sum is σ = 36270240. Its totient is φ = 8971776.

The previous prime is 21045853. The next prime is 21045883. The reversal of 21045878 is 87854012.

It is a congruent 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, 1193 + ... + 6596.

It is an arithmetic number, because the mean of its divisors is an integer number (2266890).

Almost surely, 2^21045878 is an apocalyptic number.

21045878 is a deficient number, since it is larger than the sum of its proper divisors (15224362).

21045878 is a wasteful number, since it uses less digits than its factorization.

21045878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7991.

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 21045878 is about 4587.5786641757. The cubic root of 21045878 is about 276.0931824970.

The spelling of 21045878 in words is "twenty-one million, forty-five thousand, eight hundred seventy-eight".