21545450 has 12 divisors (see below), whose sum is σ = 40074630. Its totient is φ = 8618160.

The previous prime is 21545441. The next prime is 21545471. The reversal of 21545450 is 5454512.

It can be written as a sum of positive squares in 3 ways, for example, as 19298449 + 2247001 = 4393^2 + 1499^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 215405 + ... + 215504.

Almost surely, 2^21545450 is an apocalyptic number.

21545450 is a deficient number, since it is larger than the sum of its proper divisors (18529180).

21545450 is a wasteful number, since it uses less digits than its factorization.

21545450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430921 (or 430916 counting only the distinct ones).

The product of its (nonzero) digits is 4000, while the sum is 26.

The square root of 21545450 is about 4641.7076599028. The cubic root of 21545450 is about 278.2606891664.

Adding to 21545450 its reverse (5454512), we get a palindrome (26999962).

The spelling of 21545450 in words is "twenty-one million, five hundred forty-five thousand, four hundred fifty".