20170321920 has 728 divisors, whose sum is σ = 83368129056. Its totient is φ = 4586471424.

The previous prime is 20170321909. The next prime is 20170321933. The reversal of 20170321920 is 2912307102.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

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 55 ways as a sum of consecutive naturals, for example, 104509344 + ... + 104509536.

Almost surely, 2^20170321920 is an apocalyptic number.

20170321920 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 20170321920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41684064528).

20170321920 is an abundant number, since it is smaller than the sum of its proper divisors (63197807136).

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

20170321920 is an frugal number, since it uses more digits than its factorization.

20170321920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247 (or 210 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The spelling of 20170321920 in words is "twenty billion, one hundred seventy million, three hundred twenty-one thousand, nine hundred twenty".