21806354 has 4 divisors (see below), whose sum is σ = 32709534. Its totient is φ = 10903176.

The previous prime is 21806353. The next prime is 21806381. The reversal of 21806354 is 45360812.

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., 17032129 + 4774225 = 4127^2 + 2185^2 .

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (21806353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5451587 + ... + 5451590.

Almost surely, 2^21806354 is an apocalyptic number.

21806354 is a deficient number, since it is larger than the sum of its proper divisors (10903180).

21806354 is a wasteful number, since it uses less digits than its factorization.

21806354 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10903179.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 21806354 is about 4669.7274010375. The cubic root of 21806354 is about 279.3793822247.

The spelling of 21806354 in words is "twenty-one million, eight hundred six thousand, three hundred fifty-four".