21771067 has 4 divisors (see below), whose sum is σ = 23051736. Its totient is φ = 20490400.

The previous prime is 21771053. The next prime is 21771077. The reversal of 21771067 is 76017712.

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 21771067 - 2⁷ = 21770939 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21771077) 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, 640309 + ... + 640342.

It is an arithmetic number, because the mean of its divisors is an integer number (5762934).

Almost surely, 2^21771067 is an apocalyptic number.

21771067 is a deficient number, since it is larger than the sum of its proper divisors (1280669).

21771067 is a wasteful number, since it uses less digits than its factorization.

21771067 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1280668.

The product of its (nonzero) digits is 4116, while the sum is 31.

The square root of 21771067 is about 4665.9475993629. The cubic root of 21771067 is about 279.2286038064.

Adding to 21771067 its reverse (76017712), we get a palindrome (97788779).

The spelling of 21771067 in words is "twenty-one million, seven hundred seventy-one thousand, sixty-seven".