21003700 has 18 divisors (see below), whose sum is σ = 45578246. Its totient is φ = 8401440.

The previous prime is 21003677. The next prime is 21003707. The reversal of 21003700 is 730012.

It can be written as a sum of positive squares in 3 ways, for example, as 1449616 + 19554084 = 1204^2 + 4422^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003707) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 104919 + ... + 105118.

Almost surely, 2^21003700 is an apocalyptic number.

21003700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21003700 is an abundant number, since it is smaller than the sum of its proper divisors (24574546).

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

21003700 is a wasteful number, since it uses less digits than its factorization.

21003700 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 210051 (or 210044 counting only the distinct ones).

The product of its (nonzero) digits is 42, while the sum is 13.

The square root of 21003700 is about 4582.9793802722. The cubic root of 21003700 is about 275.9086198921.

Adding to 21003700 its reverse (730012), we get a palindrome (21733712).

The spelling of 21003700 in words is "twenty-one million, three thousand, seven hundred".