21070600 has 48 divisors (see below), whose sum is σ = 49410900. Its totient is φ = 8355840.

The previous prime is 21070589. The next prime is 21070603. The reversal of 21070600 is 607012.

It can be written as a sum of positive squares in 6 ways, for example, as 7365796 + 13704804 = 2714^2 + 3702^2 .

It is not an unprimeable number, because it can be changed into a prime (21070603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27016 + ... + 27784.

Almost surely, 2^21070600 is an apocalyptic number.

21070600 is a gapful number since it is divisible by the number (20) 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 21070600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24705450).

21070600 is an abundant number, since it is smaller than the sum of its proper divisors (28340300).

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

21070600 is a wasteful number, since it uses less digits than its factorization.

21070600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 922 (or 913 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 16.

The square root of 21070600 is about 4590.2723230763. The cubic root of 21070600 is about 276.2012464894.

Adding to 21070600 its reverse (607012), we get a palindrome (21677612).

The spelling of 21070600 in words is "twenty-one million, seventy thousand, six hundred".