21533450 has 24 divisors (see below), whose sum is σ = 40226220. Its totient is φ = 8576000.

The previous prime is 21533443. The next prime is 21533459. The reversal of 21533450 is 5433512.

It can be written as a sum of positive squares in 6 ways, for example, as 9966649 + 11566801 = 3157^2 + 3401^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21533459) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12650 + ... + 14250.

Almost surely, 2^21533450 is an apocalyptic number.

21533450 is a deficient number, since it is larger than the sum of its proper divisors (18692770).

21533450 is a wasteful number, since it uses less digits than its factorization.

21533450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1882 (or 1877 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 21533450 is about 4640.4148521441. The cubic root of 21533450 is about 278.2090193493.

Adding to 21533450 its reverse (5433512), we get a palindrome (26966962).

The spelling of 21533450 in words is "twenty-one million, five hundred thirty-three thousand, four hundred fifty".