21554330 has 16 divisors (see below), whose sum is σ = 44340480. Its totient is φ = 7390032.

The previous prime is 21554311. The next prime is 21554359. The reversal of 21554330 is 3345512.

It is a junction number, because it is equal to n+sod(n) for n = 21554296 and 21554305.

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 7 ways as a sum of consecutive naturals, for example, 153890 + ... + 154029.

It is an arithmetic number, because the mean of its divisors is an integer number (2771280).

Almost surely, 2^21554330 is an apocalyptic number.

21554330 is an abundant number, since it is smaller than the sum of its proper divisors (22786150).

21554330 is a wasteful number, since it uses less digits than its factorization.

21554330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307933.

The product of its (nonzero) digits is 1800, while the sum is 23.

The square root of 21554330 is about 4642.6641058771. The cubic root of 21554330 is about 278.2989124808.

Adding to 21554330 its reverse (3345512), we get a palindrome (24899842).

It can be divided in two parts, 215 and 54330, that added together give a palindrome (54545).

The spelling of 21554330 in words is "twenty-one million, five hundred fifty-four thousand, three hundred thirty".