21723064 has 32 divisors (see below), whose sum is σ = 45872640. Its totient is φ = 9554400.

The previous prime is 21723043. The next prime is 21723067. The reversal of 21723064 is 46032712.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21723067) 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, 1254 + ... + 6709.

It is an arithmetic number, because the mean of its divisors is an integer number (1433520).

Almost surely, 2^21723064 is an apocalyptic number.

It is an amenable number.

21723064 is an abundant number, since it is smaller than the sum of its proper divisors (24149576).

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

21723064 is a wasteful number, since it uses less digits than its factorization.

21723064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8011 (or 8007 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21723064 is about 4660.8007895640. The cubic root of 21723064 is about 279.0232291823.

Adding to 21723064 its reverse (46032712), we get a palindrome (67755776).

The spelling of 21723064 in words is "twenty-one million, seven hundred twenty-three thousand, sixty-four".