21208722 has 8 divisors (see below), whose sum is σ = 42417456. Its totient is φ = 7069572.

The previous prime is 21208721. The next prime is 21208727. The reversal of 21208722 is 22780212.

It is a happy number.

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

21208722 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21208692 and 21208701.

It is not an unprimeable number, because it can be changed into a prime (21208721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1767388 + ... + 1767399.

It is an arithmetic number, because the mean of its divisors is an integer number (5302182).

Almost surely, 2^21208722 is an apocalyptic number.

21208722 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21208722 is a wasteful number, since it uses less digits than its factorization.

21208722 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3534792.

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 21208722 is about 4605.2928245661. The cubic root of 21208722 is about 276.8034506932.

Adding to 21208722 its reverse (22780212), we get a palindrome (43988934).

The spelling of 21208722 in words is "twenty-one million, two hundred eight thousand, seven hundred twenty-two".