21801972192 has 288 divisors, whose sum is σ = 78215082624. Its totient is φ = 5227084800.

The previous prime is 21801972163. The next prime is 21801972217. The reversal of 21801972192 is 29127910812.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 656467 + ... + 688877.

It is an arithmetic number, because the mean of its divisors is an integer number (271580148).

Almost surely, 2^21801972192 is an apocalyptic number.

21801972192 is a gapful number since it is divisible by the number (22) 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 21801972192, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39107541312).

21801972192 is an abundant number, since it is smaller than the sum of its proper divisors (56413110432).

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

21801972192 is a wasteful number, since it uses less digits than its factorization.

21801972192 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32462 (or 32447 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 42.

The spelling of 21801972192 in words is "twenty-one billion, eight hundred one million, nine hundred seventy-two thousand, one hundred ninety-two".