21649017 has 16 divisors (see below), whose sum is σ = 31187520. Its totient is φ = 13278912.

The previous prime is 21648997. The next prime is 21649031. The reversal of 21649017 is 71094612.

It is a happy number.

It is not a de Polignac number, because 21649017 - 2⁷ = 21648889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21649057) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 14458 + ... + 15884.

It is an arithmetic number, because the mean of its divisors is an integer number (1949220).

Almost surely, 2^21649017 is an apocalyptic number.

It is an amenable number.

21649017 is a deficient number, since it is larger than the sum of its proper divisors (9538503).

21649017 is a wasteful number, since it uses less digits than its factorization.

21649017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1832.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 21649017 is about 4652.8504166801. The cubic root of 21649017 is about 278.7058345305.

The spelling of 21649017 in words is "twenty-one million, six hundred forty-nine thousand, seventeen".