21806046 has 24 divisors (see below), whose sum is σ = 48049560. Its totient is φ = 7145136.

The previous prime is 21806041. The next prime is 21806063. The reversal of 21806046 is 64060812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21806041) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9205 + ... + 11328.

It is an arithmetic number, because the mean of its divisors is an integer number (2002065).

Almost surely, 2^21806046 is an apocalyptic number.

21806046 is an abundant number, since it is smaller than the sum of its proper divisors (26243514).

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

21806046 is a wasteful number, since it uses less digits than its factorization.

21806046 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20600 (or 20597 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21806046 is about 4669.6944225506. The cubic root of 21806046 is about 279.3780668702.

Adding to 21806046 its reverse (64060812), we get a palindrome (85866858).

The spelling of 21806046 in words is "twenty-one million, eight hundred six thousand, forty-six".