21806454 has 16 divisors (see below), whose sum is σ = 45020160. Its totient is φ = 7034280.

The previous prime is 21806453. The next prime is 21806467. The reversal of 21806454 is 45460812.

It is a plaindrome in base 11.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21806453) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58434 + ... + 58805.

It is an arithmetic number, because the mean of its divisors is an integer number (2813760).

Almost surely, 2^21806454 is an apocalyptic number.

21806454 is an abundant number, since it is smaller than the sum of its proper divisors (23213706).

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

21806454 is a wasteful number, since it uses less digits than its factorization.

21806454 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117275.

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 21806454 is about 4669.7381082883. The cubic root of 21806454 is about 279.3798092852.

The spelling of 21806454 in words is "twenty-one million, eight hundred six thousand, four hundred fifty-four".