22776821 has 4 divisors (see below), whose sum is σ = 24116652. Its totient is φ = 21436992.

The previous prime is 22776797. The next prime is 22776823. The reversal of 22776821 is 12867722.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20340100 + 2436721 = 4510^2 + 1561^2 .

It is a cyclic number.

It is not a de Polignac number, because 22776821 - 2⁶ = 22776757 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22776823) 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, 669890 + ... + 669923.

It is an arithmetic number, because the mean of its divisors is an integer number (6029163).

Almost surely, 2^22776821 is an apocalyptic number.

It is an amenable number.

22776821 is a deficient number, since it is larger than the sum of its proper divisors (1339831).

22776821 is a wasteful number, since it uses less digits than its factorization.

22776821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1339830.

The product of its digits is 18816, while the sum is 35.

The square root of 22776821 is about 4772.5067836515. The cubic root of 22776821 is about 283.4638640387.

Subtracting from 22776821 its reverse (12867722), we obtain a palindrome (9909099).

The spelling of 22776821 in words is "twenty-two million, seven hundred seventy-six thousand, eight hundred twenty-one".