21349806 has 32 divisors (see below), whose sum is σ = 45308160. Its totient is φ = 6687936.

The previous prime is 21349759. The next prime is 21349813. The reversal of 21349806 is 60894312.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14935 + ... + 16301.

It is an arithmetic number, because the mean of its divisors is an integer number (1415880).

Almost surely, 2^21349806 is an apocalyptic number.

21349806 is an abundant number, since it is smaller than the sum of its proper divisors (23958354).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21349806 is a wasteful number, since it uses less digits than its factorization.

21349806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1528.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 21349806 is about 4620.5850278942. The cubic root of 21349806 is about 277.4158758070.

It can be divided in two parts, 21349 and 806, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21349806 in words is "twenty-one million, three hundred forty-nine thousand, eight hundred six".