21218654604 has 96 divisors (see below), whose sum is σ = 57448258560. Its totient is φ = 5970454272.

The previous prime is 21218654563. The next prime is 21218654609. The reversal of 21218654604 is 40645681212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21218654609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1522114 + ... + 1535990.

It is an arithmetic number, because the mean of its divisors is an integer number (598419360).

Almost surely, 2^21218654604 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21218654604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28724129280).

21218654604 is an abundant number, since it is smaller than the sum of its proper divisors (36229603956).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21218654604 is a wasteful number, since it uses less digits than its factorization.

21218654604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14167 (or 14165 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 39.

The spelling of 21218654604 in words is "twenty-one billion, two hundred eighteen million, six hundred fifty-four thousand, six hundred four".