21399541800 has 768 divisors, whose sum is σ = 86394470400. Its totient is φ = 4260556800.

The previous prime is 21399541789. The next prime is 21399541819. The reversal of 21399541800 is 814599312.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 79552066 + ... + 79552334.

It is an arithmetic number, because the mean of its divisors is an integer number (112492800).

Almost surely, 2^21399541800 is an apocalyptic number.

21399541800 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 21399541800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43197235200).

21399541800 is an abundant number, since it is smaller than the sum of its proper divisors (64994928600).

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

21399541800 is a wasteful number, since it uses less digits than its factorization.

21399541800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 42.

The spelling of 21399541800 in words is "twenty-one billion, three hundred ninety-nine million, five hundred forty-one thousand, eight hundred".