21649028 has 6 divisors (see below), whose sum is σ = 37885806. Its totient is φ = 10824512.

The previous prime is 21648997. The next prime is 21649031. The reversal of 21649028 is 82094612.

It can be written as a sum of positive squares in only one way, i.e., 16711744 + 4937284 = 4088^2 + 2222^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21648985 and 21649003.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2706125 + ... + 2706132.

It is an arithmetic number, because the mean of its divisors is an integer number (6314301).

Almost surely, 2^21649028 is an apocalyptic number.

It is an amenable number.

21649028 is a deficient number, since it is larger than the sum of its proper divisors (16236778).

21649028 is a wasteful number, since it uses less digits than its factorization.

21649028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5412261 (or 5412259 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 32.

The square root of 21649028 is about 4652.8515987510. The cubic root of 21649028 is about 278.7058817345.

The spelling of 21649028 in words is "twenty-one million, six hundred forty-nine thousand, twenty-eight".