21979218240 has 896 divisors, whose sum is σ = 96443596800. Its totient is φ = 4598415360.

The previous prime is 21979218229. The next prime is 21979218253. The reversal of 21979218240 is 4281297912.

21979218240 is a `hidden beast` number, since 2 + 197 + 9 + 218 + 240 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 35622412 + ... + 35623028.

Almost surely, 2^21979218240 is an apocalyptic number.

21979218240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21979218240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48221798400).

21979218240 is an abundant number, since it is smaller than the sum of its proper divisors (74464378560).

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

21979218240 is a wasteful number, since it uses less digits than its factorization.

21979218240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 700 (or 684 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The spelling of 21979218240 in words is "twenty-one billion, nine hundred seventy-nine million, two hundred eighteen thousand, two hundred forty".