21554189 has 8 divisors (see below), whose sum is σ = 22827840. Its totient is φ = 20294496.

The previous prime is 21554177. The next prime is 21554209. The reversal of 21554189 is 98145512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21554189 - 2⁴ = 21554173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21554149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 224 + ... + 6569.

It is an arithmetic number, because the mean of its divisors is an integer number (2853480).

Almost surely, 2^21554189 is an apocalyptic number.

It is an amenable number.

21554189 is a deficient number, since it is larger than the sum of its proper divisors (1273651).

21554189 is a wasteful number, since it uses less digits than its factorization.

21554189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6979.

The product of its digits is 14400, while the sum is 35.

The square root of 21554189 is about 4642.6489206056. The cubic root of 21554189 is about 278.2983056386.

The spelling of 21554189 in words is "twenty-one million, five hundred fifty-four thousand, one hundred eighty-nine".