21115450 has 12 divisors (see below), whose sum is σ = 39274830. Its totient is φ = 8446160.

The previous prime is 21115439. The next prime is 21115453. The reversal of 21115450 is 5451112.

It can be written as a sum of positive squares in 3 ways, for example, as 17614809 + 3500641 = 4197^2 + 1871^2 .

It is not an unprimeable number, because it can be changed into a prime (21115453) 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, 211105 + ... + 211204.

Almost surely, 2^21115450 is an apocalyptic number.

21115450 is a deficient number, since it is larger than the sum of its proper divisors (18159380).

21115450 is a wasteful number, since it uses less digits than its factorization.

21115450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422321 (or 422316 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 19.

The square root of 21115450 is about 4595.1550572315. The cubic root of 21115450 is about 276.3970777586.

Adding to 21115450 its reverse (5451112), we get a palindrome (26566562).

The spelling of 21115450 in words is "twenty-one million, one hundred fifteen thousand, four hundred fifty".