21554318 has 4 divisors (see below), whose sum is σ = 32331480. Its totient is φ = 10777158.

The previous prime is 21554311. The next prime is 21554359. The reversal of 21554318 is 81345512.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554311) by changing a digit.

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 as a sum of consecutive naturals, namely, 5388578 + ... + 5388581.

It is an arithmetic number, because the mean of its divisors is an integer number (8082870).

Almost surely, 2^21554318 is an apocalyptic number.

21554318 is a deficient number, since it is larger than the sum of its proper divisors (10777162).

21554318 is a wasteful number, since it uses less digits than its factorization.

21554318 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10777161.

The product of its digits is 4800, while the sum is 29.

The square root of 21554318 is about 4642.6628135155. The cubic root of 21554318 is about 278.2988608348.

The spelling of 21554318 in words is "twenty-one million, five hundred fifty-four thousand, three hundred eighteen".