21393826 has 4 divisors (see below), whose sum is σ = 32090742. Its totient is φ = 10696912.

The previous prime is 21393809. The next prime is 21393847. The reversal of 21393826 is 62839312.

It is a happy number.

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., 19793601 + 1600225 = 4449^2 + 1265^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21393791 and 21393800.

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, 5348455 + ... + 5348458.

Almost surely, 2^21393826 is an apocalyptic number.

21393826 is a deficient number, since it is larger than the sum of its proper divisors (10696916).

21393826 is a wasteful number, since it uses less digits than its factorization.

21393826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10696915.

The product of its digits is 15552, while the sum is 34.

The square root of 21393826 is about 4625.3460411087. The cubic root of 21393826 is about 277.6064078033.

The spelling of 21393826 in words is "twenty-one million, three hundred ninety-three thousand, eight hundred twenty-six".