21722712 has 64 divisors (see below), whose sum is σ = 59875200. Its totient is φ = 6512640.

The previous prime is 21722707. The next prime is 21722717.

21722712 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (21722707) and next prime (21722717).

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 (21722717) 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, 27864 + ... + 28632.

It is an arithmetic number, because the mean of its divisors is an integer number (935550).

Almost surely, 2^21722712 is an apocalyptic number.

21722712 is a gapful number since it is divisible by the number (22) 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 21722712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29937600).

21722712 is an abundant number, since it is smaller than the sum of its proper divisors (38152488).

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

21722712 is a wasteful number, since it uses less digits than its factorization.

21722712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 896 (or 892 counting only the distinct ones).

The product of its digits is 784, while the sum is 24.

The square root of 21722712 is about 4660.7630276597. The cubic root of 21722712 is about 279.0217220790.

It can be divided in two parts, 2172 and 2712, that added together give a palindrome (4884).

The spelling of 21722712 in words is "twenty-one million, seven hundred twenty-two thousand, seven hundred twelve".