21001142400 has 192 divisors, whose sum is σ = 79054553280. Its totient is φ = 4800245760.

The previous prime is 21001142353. The next prime is 21001142441. The reversal of 21001142400 is 424110012.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21001142400.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 89059 + ... + 223458.

It is an arithmetic number, because the mean of its divisors is an integer number (411742465).

Almost surely, 2^21001142400 is an apocalyptic number.

21001142400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001142400 is an abundant number, since it is smaller than the sum of its proper divisors (58053410880).

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

21001142400 is a wasteful number, since it uses less digits than its factorization.

21001142400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312551 (or 312534 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21001142400 its reverse (424110012), we get a palindrome (21425252412).

The spelling of 21001142400 in words is "twenty-one billion, one million, one hundred forty-two thousand, four hundred".