21201220120 has 32 divisors (see below), whose sum is σ = 47709295200. Its totient is φ = 8479323648.

The previous prime is 21201220049. The next prime is 21201220123. The reversal of 21201220120 is 2102210212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21201220120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201220123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 296077 + ... + 360643.

It is an arithmetic number, because the mean of its divisors is an integer number (1490915475).

Almost surely, 2^21201220120 is an apocalyptic number.

21201220120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201220120 is an abundant number, since it is smaller than the sum of its proper divisors (26508075080).

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

21201220120 is a wasteful number, since it uses less digits than its factorization.

21201220120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72787 (or 72783 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21201220120 its reverse (2102210212), we get a palindrome (23303430332).

The spelling of 21201220120 in words is "twenty-one billion, two hundred one million, two hundred twenty thousand, one hundred twenty".