21003650 has 12 divisors (see below), whose sum is σ = 39066882. Its totient is φ = 8401440.

The previous prime is 21003637. The next prime is 21003659. The reversal of 21003650 is 5630012.

It can be written as a sum of positive squares in 3 ways, for example, as 20457529 + 546121 = 4523^2 + 739^2 .

It is not an unprimeable number, because it can be changed into a prime (21003659) 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, 209987 + ... + 210086.

Almost surely, 2^21003650 is an apocalyptic number.

21003650 is a deficient number, since it is larger than the sum of its proper divisors (18063232).

21003650 is a wasteful number, since it uses less digits than its factorization.

21003650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420085 (or 420080 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 17.

The square root of 21003650 is about 4582.9739253022. The cubic root of 21003650 is about 275.9084009554.

Adding to 21003650 its reverse (5630012), we get a palindrome (26633662).

The spelling of 21003650 in words is "twenty-one million, three thousand, six hundred fifty".