21549671 has 8 divisors (see below), whose sum is σ = 25317264. Its totient is φ = 18083520.

The previous prime is 21549637. The next prime is 21549677. The reversal of 21549671 is 17694512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21549671 - 2²² = 17355367 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 (21549677) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75206 + ... + 75491.

It is an arithmetic number, because the mean of its divisors is an integer number (3164658).

Almost surely, 2^21549671 is an apocalyptic number.

21549671 is a deficient number, since it is larger than the sum of its proper divisors (3767593).

21549671 is a wasteful number, since it uses less digits than its factorization.

21549671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150721.

The product of its digits is 15120, while the sum is 35.

The square root of 21549671 is about 4642.1623194369. The cubic root of 21549671 is about 278.2788594634.

The spelling of 21549671 in words is "twenty-one million, five hundred forty-nine thousand, six hundred seventy-one".