21882761 has 4 divisors (see below), whose sum is σ = 22099524. Its totient is φ = 21666000.

The previous prime is 21882739. The next prime is 21882781. The reversal of 21882761 is 16728812.

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 19193161 + 2689600 = 4381^2 + 1640^2 .

It is a cyclic number.

It is not a de Polignac number, because 21882761 - 2²² = 17688457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21882781) 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, 108230 + ... + 108431.

It is an arithmetic number, because the mean of its divisors is an integer number (5524881).

Almost surely, 2^21882761 is an apocalyptic number.

It is an amenable number.

21882761 is a deficient number, since it is larger than the sum of its proper divisors (216763).

21882761 is a wasteful number, since it uses less digits than its factorization.

21882761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 216762.

The product of its digits is 10752, while the sum is 35.

The square root of 21882761 is about 4677.9013456891. The cubic root of 21882761 is about 279.7053064472.

The spelling of 21882761 in words is "twenty-one million, eight hundred eighty-two thousand, seven hundred sixty-one".