22781561 has 8 divisors (see below), whose sum is σ = 24927264. Its totient is φ = 20648320.

The previous prime is 22781543. The next prime is 22781567. The reversal of 22781561 is 16518722.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 22781561 - 2¹⁴ = 22765177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (22781567) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 950 + ... + 6816.

It is an arithmetic number, because the mean of its divisors is an integer number (3115908).

Almost surely, 2^22781561 is an apocalyptic number.

It is an amenable number.

22781561 is a deficient number, since it is larger than the sum of its proper divisors (2145703).

22781561 is a wasteful number, since it uses less digits than its factorization.

22781561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6231.

The product of its digits is 6720, while the sum is 32.

The square root of 22781561 is about 4773.0033521882. The cubic root of 22781561 is about 283.4835262137.

Subtracting from 22781561 its sum of digits (32), we obtain a square (22781529 = 4773²).

The spelling of 22781561 in words is "twenty-two million, seven hundred eighty-one thousand, five hundred sixty-one".