21761633 has 4 divisors (see below), whose sum is σ = 21783060. Its totient is φ = 21740208.

The previous prime is 21761627. The next prime is 21761647. The reversal of 21761633 is 33616712.

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 11444689 + 10316944 = 3383^2 + 3212^2 .

It is a cyclic number.

It is not a de Polignac number, because 21761633 - 2⁴ = 21761617 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21761596 and 21761605.

It is not an unprimeable number, because it can be changed into a prime (21761833) 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, 9110 + ... + 11247.

It is an arithmetic number, because the mean of its divisors is an integer number (5445765).

Almost surely, 2^21761633 is an apocalyptic number.

It is an amenable number.

21761633 is a deficient number, since it is larger than the sum of its proper divisors (21427).

21761633 is a wasteful number, since it uses less digits than its factorization.

21761633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21426.

The product of its digits is 4536, while the sum is 29.

The square root of 21761633 is about 4664.9365483359. The cubic root of 21761633 is about 279.1882655104.

The spelling of 21761633 in words is "twenty-one million, seven hundred sixty-one thousand, six hundred thirty-three".