21101964 has 96 divisors (see below), whose sum is σ = 57435840. Its totient is φ = 5971968.

The previous prime is 21101963. The next prime is 21102023. The reversal of 21101964 is 46910112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101963) 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, 193542 + ... + 193650.

It is an arithmetic number, because the mean of its divisors is an integer number (598290).

Almost surely, 2^21101964 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21101964, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28717920).

21101964 is an abundant number, since it is smaller than the sum of its proper divisors (36333876).

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

21101964 is a wasteful number, since it uses less digits than its factorization.

21101964 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 21101964 is about 4593.6874077368. The cubic root of 21101964 is about 276.3382221998.

The spelling of 21101964 in words is "twenty-one million, one hundred one thousand, nine hundred sixty-four".