21101021000 has 128 divisors (see below), whose sum is σ = 50085565920. Its totient is φ = 8320000000.

The previous prime is 21101020991. The next prime is 21101021023. The reversal of 21101021000 is 12010112.

It can be written as a sum of positive squares in 16 ways, for example, as 1997911204 + 19103109796 = 44698^2 + 138214^2 .

It is a Harshad number since it is a multiple of its sum of digits (8).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 40500740 + ... + 40501260.

Almost surely, 2^21101021000 is an apocalyptic number.

21101021000 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 21101021000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25042782960).

21101021000 is an abundant number, since it is smaller than the sum of its proper divisors (28984544920).

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

21101021000 is a wasteful number, since it uses less digits than its factorization.

21101021000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1044 (or 1030 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

Adding to 21101021000 its reverse (12010112), we get a palindrome (21113031112).

The spelling of 21101021000 in words is "twenty-one billion, one hundred one million, twenty-one thousand".