21111211031200 has 72 divisors (see below), whose sum is σ = 51683743895868. Its totient is φ = 8420562247680.

The previous prime is 21111211031147. The next prime is 21111211031203. The reversal of 21111211031200 is 213011211112.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 1523753235216 + 19587457795984 = 1234404^2 + 4425772^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (21111211031203) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37095807 + ... + 37660606.

Almost surely, 2^{21111211031200} is an apocalyptic number.

21111211031200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111211031200 is an abundant number, since it is smaller than the sum of its proper divisors (30572532864668).

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

21111211031200 is a wasteful number, since it uses less digits than its factorization.

21111211031200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74756786 (or 74756773 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 16.

Adding to 21111211031200 its reverse (213011211112), we get a palindrome (21324222242312).

The spelling of 21111211031200 in words is "twenty-one trillion, one hundred eleven billion, two hundred eleven million, thirty-one thousand, two hundred".