21917219604 has 144 divisors (see below), whose sum is σ = 65021806080. Its totient is φ = 5703505920.

The previous prime is 21917219603. The next prime is 21917219617. The reversal of 21917219604 is 40691271912.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21917219603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 274512 + ... + 345240.

It is an arithmetic number, because the mean of its divisors is an integer number (451540320).

Almost surely, 2^21917219604 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 21917219604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32510903040).

21917219604 is an abundant number, since it is smaller than the sum of its proper divisors (43104586476).

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

21917219604 is a wasteful number, since it uses less digits than its factorization.

21917219604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70798 (or 70789 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 42.

The spelling of 21917219604 in words is "twenty-one billion, nine hundred seventeen million, two hundred nineteen thousand, six hundred four".