21101899776 has 312 divisors, whose sum is σ = 61117179264. Its totient is φ = 6471843840.

The previous prime is 21101899771. The next prime is 21101899837. The reversal of 21101899776 is 67799810112.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101899771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 297209821 + ... + 297209891.

Almost surely, 2^21101899776 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 21101899776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30558589632).

21101899776 is an abundant number, since it is smaller than the sum of its proper divisors (40015279488).

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

21101899776 is an equidigital number, since it uses as much as digits as its factorization.

21101899776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 203 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 51.

The spelling of 21101899776 in words is "twenty-one billion, one hundred one million, eight hundred ninety-nine thousand, seven hundred seventy-six".