21979642779900 has 288 divisors, whose sum is σ = 76129540939200. Its totient is φ = 5407981977600.

The previous prime is 21979642779847. The next prime is 21979642779949. The reversal of 21979642779900 is 997724697912.

21979642779900 is a `hidden beast` number, since 2 + 197 + 9 + 6 + 427 + 7 + 9 + 9 + 0 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 79925836 + ... + 80200364.

Almost surely, 2^{21979642779900} is an apocalyptic number.

21979642779900 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 21979642779900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38064770469600).

21979642779900 is an abundant number, since it is smaller than the sum of its proper divisors (54149898159300).

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

21979642779900 is a wasteful number, since it uses less digits than its factorization.

21979642779900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276846 (or 276833 counting only the distinct ones).

The product of its (nonzero) digits is 216040608, while the sum is 72.

The spelling of 21979642779900 in words is "twenty-one trillion, nine hundred seventy-nine billion, six hundred forty-two million, seven hundred seventy-nine thousand, nine hundred".