21247200000 has 648 divisors, whose sum is σ = 82824605136. Its totient is φ = 5207040000.

The previous prime is 21247199999. The next prime is 21247200043. The reversal of 21247200000 is 274212.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 93599887 + ... + 93600113.

Almost surely, 2^21247200000 is an apocalyptic number.

21247200000 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 21247200000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41412302568).

21247200000 is an abundant number, since it is smaller than the sum of its proper divisors (61577405136).

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

21247200000 is an equidigital number, since it uses as much as digits as its factorization.

21247200000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287 (or 250 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

Adding to 21247200000 its reverse (274212), we get a palindrome (21247474212).

The spelling of 21247200000 in words is "twenty-one billion, two hundred forty-seven million, two hundred thousand".