21906026 has 16 divisors (see below), whose sum is σ = 34179840. Its totient is φ = 10518240.

The previous prime is 21906019. The next prime is 21906037. The reversal of 21906026 is 62060912.

It is a super-2 number, since 2×21906026² = 959747950225352, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21905986 and 21906004.

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 in 7 ways as a sum of consecutive naturals, for example, 7205 + ... + 9783.

It is an arithmetic number, because the mean of its divisors is an integer number (2136240).

Almost surely, 2^21906026 is an apocalyptic number.

21906026 is a deficient number, since it is larger than the sum of its proper divisors (12273814).

21906026 is a wasteful number, since it uses less digits than its factorization.

21906026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2749.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 21906026 is about 4680.3873771302. The cubic root of 21906026 is about 279.8043956982.

Adding to 21906026 its reverse (62060912), we get a palindrome (83966938).

The spelling of 21906026 in words is "twenty-one million, nine hundred six thousand, twenty-six".