22840721 has 4 divisors (see below), whose sum is σ = 23271732. Its totient is φ = 22409712.

The previous prime is 22840711. The next prime is 22840739. The reversal of 22840721 is 12704822.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8673025 + 14167696 = 2945^2 + 3764^2 .

It is a cyclic number.

It is not a de Polignac number, because 22840721 - 2²² = 18646417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22840711) by changing a digit.

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, 215426 + ... + 215531.

It is an arithmetic number, because the mean of its divisors is an integer number (5817933).

Almost surely, 2^22840721 is an apocalyptic number.

It is an amenable number.

22840721 is a deficient number, since it is larger than the sum of its proper divisors (431011).

22840721 is an equidigital number, since it uses as much as digits as its factorization.

22840721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 431010.

The product of its (nonzero) digits is 1792, while the sum is 26.

The square root of 22840721 is about 4779.1966898214. The cubic root of 22840721 is about 283.7287009442.

The spelling of 22840721 in words is "twenty-two million, eight hundred forty thousand, seven hundred twenty-one".