21682771 has 4 divisors (see below), whose sum is σ = 23653944. Its totient is φ = 19711600.

The previous prime is 21682757. The next prime is 21682823. The reversal of 21682771 is 17728612.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21682771 - 2⁷ = 21682643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21683771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 985570 + ... + 985591.

It is an arithmetic number, because the mean of its divisors is an integer number (5913486).

Almost surely, 2^21682771 is an apocalyptic number.

21682771 is a deficient number, since it is larger than the sum of its proper divisors (1971173).

21682771 is a wasteful number, since it uses less digits than its factorization.

21682771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1971172.

The product of its digits is 9408, while the sum is 34.

The square root of 21682771 is about 4656.4762428257. The cubic root of 21682771 is about 278.8506071050.

The spelling of 21682771 in words is "twenty-one million, six hundred eighty-two thousand, seven hundred seventy-one".