21438466 has 16 divisors (see below), whose sum is σ = 37745856. Its totient is φ = 8939376.

The previous prime is 21438463. The next prime is 21438481. The reversal of 21438466 is 66483412.

It is not an unprimeable number, because it can be changed into a prime (21438463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20176 + ... + 21211.

It is an arithmetic number, because the mean of its divisors is an integer number (2359116).

Almost surely, 2^21438466 is an apocalyptic number.

21438466 is a deficient number, since it is larger than the sum of its proper divisors (16307390).

21438466 is a wasteful number, since it uses less digits than its factorization.

21438466 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41433.

The product of its digits is 27648, while the sum is 34.

The square root of 21438466 is about 4630.1691113824. The cubic root of 21438466 is about 277.7993566288.

It can be divided in two parts, 21438 and 466, that added together give a square (21904 = 148²).

The spelling of 21438466 in words is "twenty-one million, four hundred thirty-eight thousand, four hundred sixty-six".