21549028 has 6 divisors (see below), whose sum is σ = 37710806. Its totient is φ = 10774512.

The previous prime is 21549019. The next prime is 21549049. The reversal of 21549028 is 82094512.

It can be written as a sum of positive squares in only one way, i.e., 16064064 + 5484964 = 4008^2 + 2342^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 2693625 + ... + 2693632.

Almost surely, 2^21549028 is an apocalyptic number.

It is an amenable number.

21549028 is a deficient number, since it is larger than the sum of its proper divisors (16161778).

21549028 is a wasteful number, since it uses less digits than its factorization.

21549028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5387261 (or 5387259 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 21549028 is about 4642.0930624019. The cubic root of 21549028 is about 278.2760916704.

The spelling of 21549028 in words is "twenty-one million, five hundred forty-nine thousand, twenty-eight".