21455450 has 12 divisors (see below), whose sum is σ = 39907230. Its totient is φ = 8582160.

The previous prime is 21455443. The next prime is 21455459. The reversal of 21455450 is 5455412.

It can be written as a sum of positive squares in 3 ways, for example, as 11336689 + 10118761 = 3367^2 + 3181^2 .

It is not an unprimeable number, because it can be changed into a prime (21455459) 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, 214505 + ... + 214604.

Almost surely, 2^21455450 is an apocalyptic number.

21455450 is a deficient number, since it is larger than the sum of its proper divisors (18451780).

21455450 is a wasteful number, since it uses less digits than its factorization.

21455450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429121 (or 429116 counting only the distinct ones).

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

The square root of 21455450 is about 4632.0028065622. The cubic root of 21455450 is about 277.8726967469.

Subtracting from 21455450 its sum of digits (26), we obtain a square (21455424 = 4632²).

The spelling of 21455450 in words is "twenty-one million, four hundred fifty-five thousand, four hundred fifty".