21200040000 has 210 divisors, whose sum is σ = 75934591590. Its totient is φ = 5653248000.

The previous prime is 21200039989. The next prime is 21200040013. The reversal of 21200040000 is 4000212.

It can be written as a sum of positive squares in 5 ways, for example, as 11437019136 + 9763020864 = 106944^2 + 98808^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 330556 + ... + 389444.

Almost surely, 2^21200040000 is an apocalyptic number.

21200040000 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 21200040000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37967295795).

21200040000 is an abundant number, since it is smaller than the sum of its proper divisors (54734551590).

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

21200040000 is an equidigital number, since it uses as much as digits as its factorization.

21200040000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58927 (or 58899 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

Adding to 21200040000 its reverse (4000212), we get a palindrome (21204040212).

The spelling of 21200040000 in words is "twenty-one billion, two hundred million, forty thousand".