21722064 has 80 divisors (see below), whose sum is σ = 69078912. Its totient is φ = 5727744.

The previous prime is 21722059. The next prime is 21722069. The reversal of 21722064 is 46022712.

It is an interprime number because it is at equal distance from previous prime (21722059) and next prime (21722069).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21722069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1882 + ... + 6854.

Almost surely, 2^21722064 is an apocalyptic number.

21722064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21722064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34539456).

21722064 is an abundant number, since it is smaller than the sum of its proper divisors (47356848).

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

21722064 is a wasteful number, since it uses less digits than its factorization.

21722064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5004 (or 4998 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21722064 is about 4660.6935106269. The cubic root of 21722064 is about 279.0189475962.

Adding to 21722064 its reverse (46022712), we get a palindrome (67744776).

The spelling of 21722064 in words is "twenty-one million, seven hundred twenty-two thousand, sixty-four".