21549149 has 16 divisors (see below), whose sum is σ = 23950080. Its totient is φ = 19299840.

The previous prime is 21549131. The next prime is 21549161. The reversal of 21549149 is 94194512.

It is a cyclic number.

It is not a de Polignac number, because 21549149 - 2⁸ = 21548893 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 (21549109) 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 15 ways as a sum of consecutive naturals, for example, 29612 + ... + 30330.

It is an arithmetic number, because the mean of its divisors is an integer number (1496880).

Almost surely, 2^21549149 is an apocalyptic number.

It is an amenable number.

21549149 is a deficient number, since it is larger than the sum of its proper divisors (2400931).

21549149 is a wasteful number, since it uses less digits than its factorization.

21549149 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820.

The product of its digits is 12960, while the sum is 35.

The square root of 21549149 is about 4642.1060952977. The cubic root of 21549149 is about 278.2766125190.

The spelling of 21549149 in words is "twenty-one million, five hundred forty-nine thousand, one hundred forty-nine".