21013421400 has 144 divisors (see below), whose sum is σ = 71255848560. Its totient is φ = 5549126400.

The previous prime is 21013421371. The next prime is 21013421413. The reversal of 21013421400 is 412431012.

21013421400 is a `hidden beast` number, since 210 + 1 + 34 + 21 + 400 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 128730 + ... + 242070.

Almost surely, 2^21013421400 is an apocalyptic number.

21013421400 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 21013421400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35627924280).

21013421400 is an abundant number, since it is smaller than the sum of its proper divisors (50242427160).

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

21013421400 is a wasteful number, since it uses less digits than its factorization.

21013421400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 113466 (or 113454 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21013421400 its reverse (412431012), we get a palindrome (21425852412).

The spelling of 21013421400 in words is "twenty-one billion, thirteen million, four hundred twenty-one thousand, four hundred".