21649210 has 64 divisors (see below), whose sum is σ = 45619200. Its totient is φ = 7318080.

The previous prime is 21649207. The next prime is 21649219. The reversal of 21649210 is 1294612.

It is not an unprimeable number, because it can be changed into a prime (21649219) 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 31 ways as a sum of consecutive naturals, for example, 108691 + ... + 108889.

It is an arithmetic number, because the mean of its divisors is an integer number (712800).

Almost surely, 2^21649210 is an apocalyptic number.

21649210 is an abundant number, since it is smaller than the sum of its proper divisors (23969990).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21649210 is a wasteful number, since it uses less digits than its factorization.

21649210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 21649210 is about 4652.8711566086. The cubic root of 21649210 is about 278.7066627446.

The spelling of 21649210 in words is "twenty-one million, six hundred forty-nine thousand, two hundred ten".