21751821000 has 960 divisors, whose sum is σ = 94509866880. Its totient is φ = 4569177600.

The previous prime is 21751820941. The next prime is 21751821043. The reversal of 21751821000 is 12815712.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 95822887 + ... + 95823113.

It is an arithmetic number, because the mean of its divisors is an integer number (98447778).

Almost surely, 2^21751821000 is an apocalyptic number.

21751821000 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 21751821000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47254933440).

21751821000 is an abundant number, since it is smaller than the sum of its proper divisors (72758045880).

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

21751821000 is a wasteful number, since it uses less digits than its factorization.

21751821000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 27.

The spelling of 21751821000 in words is "twenty-one billion, seven hundred fifty-one million, eight hundred twenty-one thousand".