21772859 has 4 divisors (see below), whose sum is σ = 21972720. Its totient is φ = 21573000.

The previous prime is 21772853. The next prime is 21772897. The reversal of 21772859 is 95827712.

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 21772859 - 2⁴ = 21772843 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21772853) 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, 99767 + ... + 99984.

It is an arithmetic number, because the mean of its divisors is an integer number (5493180).

Almost surely, 2^21772859 is an apocalyptic number.

21772859 is a deficient number, since it is larger than the sum of its proper divisors (199861).

21772859 is a wasteful number, since it uses less digits than its factorization.

21772859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199860.

The product of its digits is 70560, while the sum is 41.

The square root of 21772859 is about 4666.1396250005. The cubic root of 21772859 is about 279.2362647987.

The spelling of 21772859 in words is "twenty-one million, seven hundred seventy-two thousand, eight hundred fifty-nine".