21050064 has 80 divisors (see below), whose sum is σ = 69063040. Its totient is φ = 6013440.

The previous prime is 21050059. The next prime is 21050101. The reversal of 21050064 is 46005012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 457 + ... + 6504.

It is an arithmetic number, because the mean of its divisors is an integer number (863288).

Almost surely, 2^21050064 is an apocalyptic number.

21050064 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21050064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34531520).

21050064 is an abundant number, since it is smaller than the sum of its proper divisors (48012976).

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

21050064 is a wasteful number, since it uses less digits than its factorization.

21050064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6985 (or 6973 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21050064 is about 4588.0348734507. The cubic root of 21050064 is about 276.1114861517. Note that the first 3 decimals are identical.

Adding to 21050064 its reverse (46005012), we get a palindrome (67055076).

The spelling of 21050064 in words is "twenty-one million, fifty thousand, sixty-four".