21546021000 has 256 divisors, whose sum is σ = 81347535360. Its totient is φ = 4635033600.

The previous prime is 21546020981. The next prime is 21546021011. The reversal of 21546021000 is 12064512.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 326824 + ... + 387176.

It is an arithmetic number, because the mean of its divisors is an integer number (317763810).

Almost surely, 2^21546021000 is an apocalyptic number.

21546021000 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 21546021000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40673767680).

21546021000 is an abundant number, since it is smaller than the sum of its proper divisors (59801514360).

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

21546021000 is a wasteful number, since it uses less digits than its factorization.

21546021000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60401 (or 60387 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

Adding to 21546021000 its reverse (12064512), we get a palindrome (21558085512).

The spelling of 21546021000 in words is "twenty-one billion, five hundred forty-six million, twenty-one thousand".