21111201000 has 192 divisors, whose sum is σ = 73285552080. Its totient is φ = 5477414400.

The previous prime is 21111200993. The next prime is 21111201011. The reversal of 21111201000 is 10211112.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 2395319364 + 18715881636 = 48942^2 + 136806^2 .

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 47 ways as a sum of consecutive naturals, for example, 301302 + ... + 364698.

Almost surely, 2^21111201000 is an apocalyptic number.

21111201000 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 21111201000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36642776040).

21111201000 is an abundant number, since it is smaller than the sum of its proper divisors (52174351080).

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

21111201000 is a wasteful number, since it uses less digits than its factorization.

21111201000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63461 (or 63444 counting only the distinct ones).

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

Adding to 21111201000 its reverse (10211112), we get a palindrome (21121412112).

It can be divided in two parts, 21111 and 201000, that added together give a triangular number (222111 = T₆₆₆).

The spelling of 21111201000 in words is "twenty-one billion, one hundred eleven million, two hundred one thousand".