21686677 has 4 divisors (see below), whose sum is σ = 22629600. Its totient is φ = 20743756.

The previous prime is 21686671. The next prime is 21686741. The reversal of 21686677 is 77668612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21686677 - 2³ = 21686669 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21686671) 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, 471427 + ... + 471472.

It is an arithmetic number, because the mean of its divisors is an integer number (5657400).

Almost surely, 2^21686677 is an apocalyptic number.

It is an amenable number.

21686677 is a deficient number, since it is larger than the sum of its proper divisors (942923).

21686677 is an equidigital number, since it uses as much as digits as its factorization.

21686677 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 942922.

The product of its digits is 169344, while the sum is 43.

The square root of 21686677 is about 4656.8956398013. The cubic root of 21686677 is about 278.8673504304.

The spelling of 21686677 in words is "twenty-one million, six hundred eighty-six thousand, six hundred seventy-seven".