22011561 has 32 divisors (see below), whose sum is σ = 38317440. Its totient is φ = 12312000.

The previous prime is 22011553. The next prime is 22011607. The reversal of 22011561 is 16511022.

It is not a de Polignac number, because 22011561 - 2³ = 22011553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (22011361) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1011 + ... + 6711.

It is an arithmetic number, because the mean of its divisors is an integer number (1197420).

Almost surely, 2^22011561 is an apocalyptic number.

It is an amenable number.

22011561 is a deficient number, since it is larger than the sum of its proper divisors (16305879).

22011561 is a wasteful number, since it uses less digits than its factorization.

22011561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5734 (or 5728 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 22011561 is about 4691.6480046994. The cubic root of 22011561 is about 280.2530068594.

Adding to 22011561 its reverse (16511022), we get a palindrome (38522583).

It can be divided in two parts, 220 and 11561, that added together give a triangular number (11781 = T₁₅₃).

The spelling of 22011561 in words is "twenty-two million, eleven thousand, five hundred sixty-one".