21418806 has 16 divisors (see below), whose sum is σ = 42955200. Its totient is φ = 7120008.

The previous prime is 21418801. The next prime is 21418807. The reversal of 21418806 is 60881412.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21418801) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 2436 + ... + 6983.

It is an arithmetic number, because the mean of its divisors is an integer number (2684700).

Almost surely, 2^21418806 is an apocalyptic number.

21418806 is an abundant number, since it is smaller than the sum of its proper divisors (21536394).

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

21418806 is a wasteful number, since it uses less digits than its factorization.

21418806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9803.

The product of its (nonzero) digits is 3072, while the sum is 30.

The square root of 21418806 is about 4628.0455918238. The cubic root of 21418806 is about 277.7144126518.

The spelling of 21418806 in words is "twenty-one million, four hundred eighteen thousand, eight hundred six".