22007721 has 4 divisors (see below), whose sum is σ = 29343632. Its totient is φ = 14671812.

The previous prime is 22007683. The next prime is 22007729. The reversal of 22007721 is 12770022.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 22007721 - 2¹¹ = 22005673 is a prime.

It is a super-2 number, since 2×22007721² = 968679567227682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22007729) 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, 3667951 + ... + 3667956.

It is an arithmetic number, because the mean of its divisors is an integer number (7335908).

Almost surely, 2^22007721 is an apocalyptic number.

It is an amenable number.

22007721 is a deficient number, since it is larger than the sum of its proper divisors (7335911).

22007721 is an equidigital number, since it uses as much as digits as its factorization.

22007721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7335910.

The product of its (nonzero) digits is 392, while the sum is 21.

The square root of 22007721 is about 4691.2387489873. The cubic root of 22007721 is about 280.2367088462.

Adding to 22007721 its reverse (12770022), we get a palindrome (34777743).

The spelling of 22007721 in words is "twenty-two million, seven thousand, seven hundred twenty-one".