21090450 has 24 divisors (see below), whose sum is σ = 52304688. Its totient is φ = 5624080.

The previous prime is 21090439. The next prime is 21090457. The reversal of 21090450 is 5409012.

It is not an unprimeable number, because it can be changed into a prime (21090457) 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, 70152 + ... + 70451.

It is an arithmetic number, because the mean of its divisors is an integer number (2179362).

Almost surely, 2^21090450 is an apocalyptic number.

21090450 is an abundant number, since it is smaller than the sum of its proper divisors (31214238).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21090450 is a wasteful number, since it uses less digits than its factorization.

21090450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140618 (or 140613 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 21090450 is about 4592.4339951708. The cubic root of 21090450 is about 276.2879529901.

Adding to 21090450 its reverse (5409012), we get a palindrome (26499462).

The spelling of 21090450 in words is "twenty-one million, ninety thousand, four hundred fifty".