21634826 has 4 divisors (see below), whose sum is σ = 32452242. Its totient is φ = 10817412.

The previous prime is 21634813. The next prime is 21634849. The reversal of 21634826 is 62843612.

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., 21631801 + 3025 = 4651^2 + 55^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21634792 and 21634801.

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, 5408705 + ... + 5408708.

Almost surely, 2^21634826 is an apocalyptic number.

21634826 is a deficient number, since it is larger than the sum of its proper divisors (10817416).

21634826 is a wasteful number, since it uses less digits than its factorization.

21634826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10817415.

The product of its digits is 13824, while the sum is 32.

The square root of 21634826 is about 4651.3251875138. The cubic root of 21634826 is about 278.6449236970.

The spelling of 21634826 in words is "twenty-one million, six hundred thirty-four thousand, eight hundred twenty-six".