21729020320 has 96 divisors (see below), whose sum is σ = 59662915200. Its totient is φ = 7323657216.

The previous prime is 21729020273. The next prime is 21729020323. The reversal of 21729020320 is 2302092712.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (21729020323) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 98335 + ... + 230494.

It is an arithmetic number, because the mean of its divisors is an integer number (621488700).

Almost surely, 2^21729020320 is an apocalyptic number.

21729020320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21729020320 is an abundant number, since it is smaller than the sum of its proper divisors (37933894880).

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

21729020320 is a wasteful number, since it uses less digits than its factorization.

21729020320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328910 (or 328902 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The spelling of 21729020320 in words is "twenty-one billion, seven hundred twenty-nine million, twenty thousand, three hundred twenty".