21055571018 has 8 divisors (see below), whose sum is σ = 32054750112. Its totient is φ = 10370654316.

The previous prime is 21055570979. The next prime is 21055571027. The reversal of 21055571018 is 81017555012.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 78565430 + ... + 78565697.

It is an arithmetic number, because the mean of its divisors is an integer number (4006843764).

Almost surely, 2^21055571018 is an apocalyptic number.

21055571018 is a deficient number, since it is larger than the sum of its proper divisors (10999179094).

21055571018 is a wasteful number, since it uses less digits than its factorization.

21055571018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157131196.

The product of its (nonzero) digits is 14000, while the sum is 35.

The spelling of 21055571018 in words is "twenty-one billion, fifty-five million, five hundred seventy-one thousand, eighteen".