22147721 has 4 divisors (see below), whose sum is σ = 22478352. Its totient is φ = 21817092.

The previous prime is 22147717. The next prime is 22147751. The reversal of 22147721 is 12774122.

22147721 = T₁₁₀ + T₁₁₁ + ... + T₅₁₁.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12774122 = 2 ⋅6387061.

It is a cyclic number.

It is not a de Polignac number, because 22147721 - 2² = 22147717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22147751) 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, 165215 + ... + 165348.

It is an arithmetic number, because the mean of its divisors is an integer number (5619588).

Almost surely, 2^22147721 is an apocalyptic number.

It is an amenable number.

22147721 is a deficient number, since it is larger than the sum of its proper divisors (330631).

22147721 is an equidigital number, since it uses as much as digits as its factorization.

22147721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330630.

The product of its digits is 1568, while the sum is 26.

The square root of 22147721 is about 4706.1365258564. The cubic root of 22147721 is about 280.8296861835.

The spelling of 22147721 in words is "twenty-two million, one hundred forty-seven thousand, seven hundred twenty-one".