21011012100000 has 432 divisors, whose sum is σ = 80427677783544. Its totient is φ = 5171938560000.

The previous prime is 21011012099989. The next prime is 21011012100053. The reversal of 21011012100000 is 121011012.

It is a happy number.

It can be written as a sum of positive squares in 12 ways, for example, as 13760034140304 + 7250977959696 = 3709452^2 + 2692764^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 10802094 + ... + 12597906.

Almost surely, 2^{21011012100000} is an apocalyptic number.

21011012100000 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 21011012100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40213838891772).

21011012100000 is an abundant number, since it is smaller than the sum of its proper divisors (59416665683544).

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

21011012100000 is a wasteful number, since it uses less digits than its factorization.

21011012100000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1795867 (or 1795836 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21011012100000 its reverse (121011012), we get a palindrome (21011133111012).

The spelling of 21011012100000 in words is "twenty-one trillion, eleven billion, twelve million, one hundred thousand".