21000030000 has 100 divisors (see below), whose sum is σ = 67790993688. Its totient is φ = 5600000000.

The previous prime is 21000029987. The next prime is 21000030047. The reversal of 21000030000 is 3000012.

It is a tau number, because it is divible by the number of its divisors (100).

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 320001 + ... + 380000.

Almost surely, 2^21000030000 is an apocalyptic number.

21000030000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000030000 is an abundant number, since it is smaller than the sum of its proper divisors (46790963688).

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

21000030000 is an equidigital number, since it uses as much as digits as its factorization.

21000030000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 700032 (or 700011 counting only the distinct ones).

The product of its (nonzero) digits is 6, while the sum is 6.

Adding to 21000030000 its reverse (3000012), we get a palindrome (21003030012).

The spelling of 21000030000 in words is "twenty-one billion, thirty thousand".