21649033 has 12 divisors (see below), whose sum is σ = 25866372. Its totient is φ = 18053280.

The previous prime is 21649031. The next prime is 21649057. The reversal of 21649033 is 33094612.

It can be written as a sum of positive squares in 2 ways, for example, as 13046544 + 8602489 = 3612^2 + 2933^2 .

It is not a de Polignac number, because 21649033 - 2¹ = 21649031 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21648992 and 21649010.

It is not an unprimeable number, because it can be changed into a prime (21649031) 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 11 ways as a sum of consecutive naturals, for example, 4158 + ... + 7783.

It is an arithmetic number, because the mean of its divisors is an integer number (2155531).

Almost surely, 2^21649033 is an apocalyptic number.

It is an amenable number.

21649033 is a deficient number, since it is larger than the sum of its proper divisors (4217339).

21649033 is a wasteful number, since it uses less digits than its factorization.

21649033 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11992 (or 11985 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 21649033 is about 4652.8521360559. The cubic root of 21649033 is about 278.7059031909.

The spelling of 21649033 in words is "twenty-one million, six hundred forty-nine thousand, thirty-three".