21423450 has 48 divisors (see below), whose sum is σ = 55933920. Its totient is φ = 5411520.

The previous prime is 21423421. The next prime is 21423487. The reversal of 21423450 is 5432412.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 909 + ... + 6608.

It is an arithmetic number, because the mean of its divisors is an integer number (1165290).

Almost surely, 2^21423450 is an apocalyptic number.

21423450 is an abundant number, since it is smaller than the sum of its proper divisors (34510470).

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

21423450 is a wasteful number, since it uses less digits than its factorization.

21423450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7551 (or 7546 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 21.

The square root of 21423450 is about 4628.5472882968. The cubic root of 21423450 is about 277.7344824374.

Adding to 21423450 its reverse (5432412), we get a palindrome (26855862).

The spelling of 21423450 in words is "twenty-one million, four hundred twenty-three thousand, four hundred fifty".