21554143 has 8 divisors (see below), whose sum is σ = 23249408. Its totient is φ = 19864224.

The previous prime is 21554111. The next prime is 21554149. The reversal of 21554143 is 34145512.

It is a happy number.

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 21554143 - 2⁵ = 21554111 is a prime.

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, 12130 + ... + 13792.

It is an arithmetic number, because the mean of its divisors is an integer number (2906176).

Almost surely, 2^21554143 is an apocalyptic number.

21554143 is a deficient number, since it is larger than the sum of its proper divisors (1695265).

21554143 is a wasteful number, since it uses less digits than its factorization.

21554143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2673.

The product of its digits is 2400, while the sum is 25.

The square root of 21554143 is about 4642.6439665346. The cubic root of 21554143 is about 278.2981076611.

Adding to 21554143 its reverse (34145512), we get a palindrome (55699655).

The spelling of 21554143 in words is "twenty-one million, five hundred fifty-four thousand, one hundred forty-three".