22128749 has 4 divisors (see below), whose sum is σ = 23293440. Its totient is φ = 20964060.

The previous prime is 22128739. The next prime is 22128767. The reversal of 22128749 is 94782122.

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: 94782122 = 2 ⋅47391061.

It is a cyclic number.

It is not a de Polignac number, because 22128749 - 2¹² = 22124653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22128739) 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, 582317 + ... + 582354.

It is an arithmetic number, because the mean of its divisors is an integer number (5823360).

Almost surely, 2^22128749 is an apocalyptic number.

It is an amenable number.

22128749 is a deficient number, since it is larger than the sum of its proper divisors (1164691).

22128749 is a wasteful number, since it uses less digits than its factorization.

22128749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1164690.

The product of its digits is 16128, while the sum is 35.

The square root of 22128749 is about 4704.1204278802. The cubic root of 22128749 is about 280.7494759316.

The spelling of 22128749 in words is "twenty-two million, one hundred twenty-eight thousand, seven hundred forty-nine".