21030215400 has 288 divisors, whose sum is σ = 72828177240. Its totient is φ = 5434490880.

The previous prime is 21030215399. The next prime is 21030215443. The reversal of 21030215400 is 451203012.

21030215400 is a `hidden beast` number, since 2 + 103 + 0 + 21 + 540 + 0 = 666.

It can be written as a sum of positive squares in 12 ways, for example, as 140138244 + 20890077156 = 11838^2 + 144534^2 .

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, 22443732 + ... + 22444668.

Almost surely, 2^21030215400 is an apocalyptic number.

21030215400 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 21030215400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36414088620).

21030215400 is an abundant number, since it is smaller than the sum of its proper divisors (51797961840).

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

21030215400 is a wasteful number, since it uses less digits than its factorization.

21030215400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1333 (or 1321 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

Adding to 21030215400 its reverse (451203012), we get a palindrome (21481418412).

The spelling of 21030215400 in words is "twenty-one billion, thirty million, two hundred fifteen thousand, four hundred".