21549271 has 4 divisors (see below), whose sum is σ = 21623112. Its totient is φ = 21475432.

The previous prime is 21549257. The next prime is 21549289. The reversal of 21549271 is 17294512.

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 21549271 - 2⁹ = 21548759 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 (21549221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36481 + ... + 37066.

It is an arithmetic number, because the mean of its divisors is an integer number (5405778).

Almost surely, 2^21549271 is an apocalyptic number.

21549271 is a deficient number, since it is larger than the sum of its proper divisors (73841).

21549271 is an equidigital number, since it uses as much as digits as its factorization.

21549271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73840.

The product of its digits is 5040, while the sum is 31.

The square root of 21549271 is about 4642.1192358663. The cubic root of 21549271 is about 278.2771376702.

The spelling of 21549271 in words is "twenty-one million, five hundred forty-nine thousand, two hundred seventy-one".