21424554 has 32 divisors (see below), whose sum is σ = 48901440. Its totient is φ = 6947856.

The previous prime is 21424549. The next prime is 21424577. The reversal of 21424554 is 45542412.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

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 15 ways as a sum of consecutive naturals, for example, 3364 + ... + 7359.

It is an arithmetic number, because the mean of its divisors is an integer number (1528170).

Almost surely, 2^21424554 is an apocalyptic number.

21424554 is an abundant number, since it is smaller than the sum of its proper divisors (27476886).

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

21424554 is a wasteful number, since it uses less digits than its factorization.

21424554 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10771 (or 10765 counting only the distinct ones).

The product of its digits is 6400, while the sum is 27.

The square root of 21424554 is about 4628.6665466417. Note that the first 3 decimals coincide. The cubic root of 21424554 is about 277.7392531225.

Adding to 21424554 its reverse (45542412), we get a palindrome (66966966).

The spelling of 21424554 in words is "twenty-one million, four hundred twenty-four thousand, five hundred fifty-four".