21589378 has 4 divisors (see below), whose sum is σ = 32384070. Its totient is φ = 10794688.

The previous prime is 21589367. The next prime is 21589409. The reversal of 21589378 is 87398512.

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

It can be written as a sum of positive squares in only one way, i.e., 16867449 + 4721929 = 4107^2 + 2173^2 .

It is a super-2 number, since 2×21589378² = 932202484853768, which contains 22 as substring.

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 as a sum of consecutive naturals, namely, 5397343 + ... + 5397346.

Almost surely, 2^21589378 is an apocalyptic number.

21589378 is a deficient number, since it is larger than the sum of its proper divisors (10794692).

21589378 is a wasteful number, since it uses less digits than its factorization.

21589378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10794691.

The product of its digits is 120960, while the sum is 43.

The square root of 21589378 is about 4646.4371296726. The cubic root of 21589378 is about 278.4496716459.

The spelling of 21589378 in words is "twenty-one million, five hundred eighty-nine thousand, three hundred seventy-eight".