21677671 has 4 divisors (see below), whose sum is σ = 22263592. Its totient is φ = 21091752.

The previous prime is 21677653. The next prime is 21677681. The reversal of 21677671 is 17677612.

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 21677671 - 2⁵ = 21677639 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 585883 = 21677671 / (2 + 1 + 6 + 7 + 7 + 6 + 7 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21677671.

It is a congruent number.

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 (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 292905 + ... + 292978.

It is an arithmetic number, because the mean of its divisors is an integer number (5565898).

Almost surely, 2^21677671 is an apocalyptic number.

21677671 is a deficient number, since it is larger than the sum of its proper divisors (585921).

21677671 is an equidigital number, since it uses as much as digits as its factorization.

21677671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 585920.

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

The square root of 21677671 is about 4655.9285862221. The cubic root of 21677671 is about 278.8287425931.

The spelling of 21677671 in words is "twenty-one million, six hundred seventy-seven thousand, six hundred seventy-one".