21111000021000 has 96 divisors (see below), whose sum is σ = 71355180101400. Its totient is φ = 5629600003200.

The previous prime is 21111000020963. The next prime is 21111000021029. The reversal of 21111000021000 is 12000011112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 11019996451044 + 10091003569956 = 3319638^2 + 3176634^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1172824335 + ... + 1172842334.

Almost surely, 2^{21111000021000} is an apocalyptic number.

21111000021000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111000021000 is an abundant number, since it is smaller than the sum of its proper divisors (50244180080400).

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

21111000021000 is a wasteful number, since it uses less digits than its factorization.

21111000021000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2345666696 (or 2345666679 counting only the distinct ones).

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

Adding to 21111000021000 its reverse (12000011112), we get a palindrome (21123000032112).

The spelling of 21111000021000 in words is "twenty-one trillion, one hundred eleven billion, twenty-one thousand".