21205350 has 36 divisors (see below), whose sum is σ = 56972916. Its totient is φ = 5654640.

The previous prime is 21205313. The next prime is 21205361. The reversal of 21205350 is 5350212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

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 17 ways as a sum of consecutive naturals, for example, 23112 + ... + 24011.

It is an arithmetic number, because the mean of its divisors is an integer number (1582581).

Almost surely, 2^21205350 is an apocalyptic number.

21205350 is an abundant number, since it is smaller than the sum of its proper divisors (35767566).

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

21205350 is a wasteful number, since it uses less digits than its factorization.

21205350 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47141 (or 47133 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 21205350 is about 4604.9267095145. The cubic root of 21205350 is about 276.7887801454.

Adding to 21205350 its reverse (5350212), we get a palindrome (26555562).

The spelling of 21205350 in words is "twenty-one million, two hundred five thousand, three hundred fifty".