21000553111 has 8 divisors (see below), whose sum is σ = 22136266880. Its totient is φ = 19867881528.

The previous prime is 21000553109. The next prime is 21000553157. The reversal of 21000553111 is 11135500012.

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 21000553111 - 2¹ = 21000553109 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000553181) 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, 746361 + ... + 773986.

It is an arithmetic number, because the mean of its divisors is an integer number (2767033360).

Almost surely, 2^21000553111 is an apocalyptic number.

21000553111 is a deficient number, since it is larger than the sum of its proper divisors (1135713769).

21000553111 is a wasteful number, since it uses less digits than its factorization.

21000553111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1521093.

The product of its (nonzero) digits is 150, while the sum is 19.

The spelling of 21000553111 in words is "twenty-one billion, five hundred fifty-three thousand, one hundred eleven".