21000202400 has 108 divisors (see below), whose sum is σ = 52490417742. Its totient is φ = 8204152320.

The previous prime is 21000202351. The next prime is 21000202411. The reversal of 21000202400 is 420200012.

It can be written as a sum of positive squares in 3 ways, for example, as 20233355536 + 766846864 = 142244^2 + 27692^2 .

It is a super-3 number, since 3×21000202400³ (a number of 32 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1472102 + ... + 1486298.

Almost surely, 2^21000202400 is an apocalyptic number.

21000202400 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 21000202400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26245208871).

21000202400 is an abundant number, since it is smaller than the sum of its proper divisors (31490215342).

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

21000202400 is a wasteful number, since it uses less digits than its factorization.

21000202400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14303 (or 14247 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 11.

Adding to 21000202400 its reverse (420200012), we get a palindrome (21420402412).

The spelling of 21000202400 in words is "twenty-one billion, two hundred two thousand, four hundred".