21723146 has 8 divisors (see below), whose sum is σ = 33708420. Its totient is φ = 10487008.

The previous prime is 21723113. The next prime is 21723167. The reversal of 21723146 is 64132712.

It can be written as a sum of positive squares in 2 ways, for example, as 21058921 + 664225 = 4589^2 + 815^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 187211 + ... + 187326.

Almost surely, 2^21723146 is an apocalyptic number.

21723146 is a deficient number, since it is larger than the sum of its proper divisors (11985274).

21723146 is a wasteful number, since it uses less digits than its factorization.

21723146 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 374568.

The product of its digits is 2016, while the sum is 26.

The square root of 21723146 is about 4660.8095863273. The cubic root of 21723146 is about 279.0235802666.

Adding to 21723146 its reverse (64132712), we get a palindrome (85855858).

The spelling of 21723146 in words is "twenty-one million, seven hundred twenty-three thousand, one hundred forty-six".