21518117084 has 48 divisors (see below), whose sum is σ = 41340511296. Its totient is φ = 9768844800.

The previous prime is 21518117053. The next prime is 21518117087. The reversal of 21518117084 is 48071181512.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21518117087) 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, 62474 + ... + 216654.

It is an arithmetic number, because the mean of its divisors is an integer number (861260652).

Almost surely, 2^21518117084 is an apocalyptic number.

It is an amenable number.

21518117084 is a deficient number, since it is larger than the sum of its proper divisors (19822394212).

21518117084 is a wasteful number, since it uses less digits than its factorization.

21518117084 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154286 (or 154284 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 38.

Adding to 21518117084 its reverse (48071181512), we get a palindrome (69589298596).

The spelling of 21518117084 in words is "twenty-one billion, five hundred eighteen million, one hundred seventeen thousand, eighty-four".