21200000002120 has 128 divisors (see below), whose sum is σ = 49096804790880. Its totient is φ = 8235002880000.

The previous prime is 21200000002091. The next prime is 21200000002171. The reversal of 21200000002120 is 2120000000212.

It can be written as a sum of positive squares in 16 ways, for example, as 5749550343684 + 15450449658436 = 2397822^2 + 3930706^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21200000002097 and 21200000002106.

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, 758184940 + ... + 758212900.

Almost surely, 2^{21200000002120} is an apocalyptic number.

21200000002120 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 21200000002120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24548402395440).

21200000002120 is an abundant number, since it is smaller than the sum of its proper divisors (27896804788760).

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

21200000002120 is a wasteful number, since it uses less digits than its factorization.

21200000002120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31667 (or 31663 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

21200000002120 divided by its sum of digits (10) gives a palindrome (2120000000212).

Adding to 21200000002120 its reverse (2120000000212), we get a palindrome (23320000002332).

It can be divided in two parts, 2120000000 and 2120, that multiplied together give a square (4494400000000 = 2120000²).

The spelling of 21200000002120 in words is "twenty-one trillion, two hundred billion, two thousand, one hundred twenty".