21891289220 has 48 divisors (see below), whose sum is σ = 48163035648. Its totient is φ = 8347553280.

The previous prime is 21891289219. The next prime is 21891289237. The reversal of 21891289220 is 2298219812.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 221957 + ... + 305036.

It is an arithmetic number, because the mean of its divisors is an integer number (1003396576).

Almost surely, 2^21891289220 is an apocalyptic number.

21891289220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21891289220 is an abundant number, since it is smaller than the sum of its proper divisors (26271746428).

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

21891289220 is a wasteful number, since it uses less digits than its factorization.

21891289220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 527100 (or 527098 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 44.

The spelling of 21891289220 in words is "twenty-one billion, eight hundred ninety-one million, two hundred eighty-nine thousand, two hundred twenty".