21045650 has 24 divisors (see below), whose sum is σ = 39292500. Its totient is φ = 8386560.

The previous prime is 21045649. The next prime is 21045691. The reversal of 21045650 is 5654012.

It can be written as a sum of positive squares in 6 ways, for example, as 4456321 + 16589329 = 2111^2 + 4073^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16226 + ... + 17474.

Almost surely, 2^21045650 is an apocalyptic number.

21045650 is a deficient number, since it is larger than the sum of its proper divisors (18246850).

21045650 is a wasteful number, since it uses less digits than its factorization.

21045650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1598 (or 1593 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 23.

The square root of 21045650 is about 4587.5538143983. The cubic root of 21045650 is about 276.0921854772.

Adding to 21045650 its reverse (5654012), we get a palindrome (26699662).

The spelling of 21045650 in words is "twenty-one million, forty-five thousand, six hundred fifty".