21677617 has 4 divisors (see below), whose sum is σ = 23345140. Its totient is φ = 20010096.

The previous prime is 21677611. The next prime is 21677629. The reversal of 21677617 is 71677612.

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 11999296 + 9678321 = 3464^2 + 3111^2 .

It is a cyclic number.

It is not a de Polignac number, because 21677617 - 2³ = 21677609 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21677611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 833742 + ... + 833767.

It is an arithmetic number, because the mean of its divisors is an integer number (5836285).

Almost surely, 2^21677617 is an apocalyptic number.

It is an amenable number.

21677617 is a deficient number, since it is larger than the sum of its proper divisors (1667523).

21677617 is a wasteful number, since it uses less digits than its factorization.

21677617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1667522.

The product of its digits is 24696, while the sum is 37.

The square root of 21677617 is about 4655.9227871605. The cubic root of 21677617 is about 278.8285110681.

The spelling of 21677617 in words is "twenty-one million, six hundred seventy-seven thousand, six hundred seventeen".