18865989551 has 16 divisors (see below), whose sum is σ = 19694461824. Its totient is φ = 18057571584.

The previous prime is 18865989491. The next prime is 18865989559. The reversal of 18865989551 is 15598956881.

It is a cyclic number.

It is not a de Polignac number, because 18865989551 - 2⁶ = 18865989487 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 (18865989559) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 767585 + ... + 791781.

It is an arithmetic number, because the mean of its divisors is an integer number (1230903864).

Almost surely, 2^18865989551 is an apocalyptic number.

18865989551 is a deficient number, since it is larger than the sum of its proper divisors (828472273).

18865989551 is a wasteful number, since it uses less digits than its factorization.

18865989551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24610.

The product of its digits is 31104000, while the sum is 65.

The spelling of 18865989551 in words is "eighteen billion, eight hundred sixty-five million, nine hundred eighty-nine thousand, five hundred fifty-one".