21871069920 has 144 divisors (see below), whose sum is σ = 85297212000. Its totient is φ = 4999099392.

The previous prime is 21871069877. The next prime is 21871069921. The reversal of 21871069920 is 2996017812.

It is a tau number, because it is divible by the number of its divisors (144).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21871069921) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1074795 + ... + 1094954.

It is an arithmetic number, because the mean of its divisors is an integer number (592341750).

Almost surely, 2^21871069920 is an apocalyptic number.

21871069920 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21871069920 is an abundant number, since it is smaller than the sum of its proper divisors (63426142080).

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

21871069920 is a wasteful number, since it uses less digits than its factorization.

21871069920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2169777 (or 2169766 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The spelling of 21871069920 in words is "twenty-one billion, eight hundred seventy-one million, sixty-nine thousand, nine hundred twenty".