21001100320 has 48 divisors (see below), whose sum is σ = 49632186240. Its totient is φ = 8397547264.

The previous prime is 21001100251. The next prime is 21001100339. The reversal of 21001100320 is 2300110012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21001100297 and 21001100306.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 477999 + ... + 520081.

It is an arithmetic number, because the mean of its divisors is an integer number (1034003880).

Almost surely, 2^21001100320 is an apocalyptic number.

21001100320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001100320 is an abundant number, since it is smaller than the sum of its proper divisors (28631085920).

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

21001100320 is a wasteful number, since it uses less digits than its factorization.

21001100320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45217 (or 45209 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 21001100320 its reverse (2300110012), we get a palindrome (23301210332).

The spelling of 21001100320 in words is "twenty-one billion, one million, one hundred thousand, three hundred twenty".