21358478 has 4 divisors (see below), whose sum is σ = 32037720. Its totient is φ = 10679238.

The previous prime is 21358457. The next prime is 21358501. The reversal of 21358478 is 87485312.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5339618 + ... + 5339621.

It is an arithmetic number, because the mean of its divisors is an integer number (8009430).

Almost surely, 2^21358478 is an apocalyptic number.

21358478 is a deficient number, since it is larger than the sum of its proper divisors (10679242).

21358478 is a wasteful number, since it uses less digits than its factorization.

21358478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10679241.

The product of its digits is 53760, while the sum is 38.

The square root of 21358478 is about 4621.5233419296. The cubic root of 21358478 is about 277.4534315709.

The spelling of 21358478 in words is "twenty-one million, three hundred fifty-eight thousand, four hundred seventy-eight".