21554065 has 16 divisors (see below), whose sum is σ = 27998208. Its totient is φ = 15834816.

The previous prime is 21554063. The next prime is 21554077. The reversal of 21554065 is 56045512.

It is a cyclic number.

It is not a de Polignac number, because 21554065 - 2¹ = 21554063 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21554063) 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 in 15 ways as a sum of consecutive naturals, for example, 13752 + ... + 15238.

It is an arithmetic number, because the mean of its divisors is an integer number (1749888).

Almost surely, 2^21554065 is an apocalyptic number.

It is an amenable number.

21554065 is a deficient number, since it is larger than the sum of its proper divisors (6444143).

21554065 is a wasteful number, since it uses less digits than its factorization.

21554065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1728.

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 21554065 is about 4642.6355661413. The cubic root of 21554065 is about 278.2977719596.

Adding to 21554065 its reverse (56045512), we get a palindrome (77599577).

The spelling of 21554065 in words is "twenty-one million, five hundred fifty-four thousand, sixty-five".