21210450 has 24 divisors (see below), whose sum is σ = 52602288. Its totient is φ = 5656080.

The previous prime is 21210433. The next prime is 21210461. The reversal of 21210450 is 5401212.

It is a Harshad number since it is a multiple of its sum of digits (15).

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 11 ways as a sum of consecutive naturals, for example, 70552 + ... + 70851.

It is an arithmetic number, because the mean of its divisors is an integer number (2191762).

Almost surely, 2^21210450 is an apocalyptic number.

21210450 is an abundant number, since it is smaller than the sum of its proper divisors (31391838).

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

21210450 is a wasteful number, since it uses less digits than its factorization.

21210450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141418 (or 141413 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21210450 is about 4605.4804309648. The cubic root of 21210450 is about 276.8109680937.

Adding to 21210450 its reverse (5401212), we get a palindrome (26611662).

The spelling of 21210450 in words is "twenty-one million, two hundred ten thousand, four hundred fifty".