21921750144 has 256 divisors, whose sum is σ = 75455520000. Its totient is φ = 6263018496.

The previous prime is 21921750143. The next prime is 21921750197. The reversal of 21921750144 is 44105712912.

21921750144 is a `hidden beast` number, since 21 + 92 + 1 + 7 + 501 + 44 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21921750099 and 21921750108.

It is not an unprimeable number, because it can be changed into a prime (21921750143) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1176162 + ... + 1194654.

It is an arithmetic number, because the mean of its divisors is an integer number (294748125).

Almost surely, 2^21921750144 is an apocalyptic number.

21921750144 is a gapful number since it is divisible by the number (24) 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 21921750144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37727760000).

21921750144 is an abundant number, since it is smaller than the sum of its proper divisors (53533769856).

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

21921750144 is an equidigital number, since it uses as much as digits as its factorization.

21921750144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18537 (or 18505 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

It can be divided in two parts, 219217 and 50144, that added together give a square (269361 = 519²).

The spelling of 21921750144 in words is "twenty-one billion, nine hundred twenty-one million, seven hundred fifty thousand, one hundred forty-four".