21918689100 has 720 divisors, whose sum is σ = 89655261696. Its totient is φ = 4499712000.

The previous prime is 21918689087. The next prime is 21918689131. The reversal of 21918689100 is 198681912.

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

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

It is an unprimeable number.

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 239 ways as a sum of consecutive naturals, for example, 70477945 + ... + 70478255.

Almost surely, 2^21918689100 is an apocalyptic number.

21918689100 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 21918689100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44827630848).

21918689100 is an abundant number, since it is smaller than the sum of its proper divisors (67736572596).

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

21918689100 is a wasteful number, since it uses less digits than its factorization.

21918689100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 468 (or 452 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 45.

The spelling of 21918689100 in words is "twenty-one billion, nine hundred eighteen million, six hundred eighty-nine thousand, one hundred".