21231220200 has 48 divisors (see below), whose sum is σ = 65816784480. Its totient is φ = 5661658560.

The previous prime is 21231220193. The next prime is 21231220229. The reversal of 21231220200 is 202213212.

It is a happy number.

It is a super-2 number, since 2×21231220200² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21231220200.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17692084 + ... + 17693283.

It is an arithmetic number, because the mean of its divisors is an integer number (1371183010).

Almost surely, 2^21231220200 is an apocalyptic number.

21231220200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21231220200 is an abundant number, since it is smaller than the sum of its proper divisors (44585564280).

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

21231220200 is a wasteful number, since it uses less digits than its factorization.

21231220200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35385386 (or 35385377 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 21231220200 its reverse (202213212), we get a palindrome (21433433412).

The spelling of 21231220200 in words is "twenty-one billion, two hundred thirty-one million, two hundred twenty thousand, two hundred".