20121605220 has 48 divisors (see below), whose sum is σ = 57539236608. Its totient is φ = 5251595520.

The previous prime is 20121605191. The next prime is 20121605227. The reversal of 20121605220 is 2250612102.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (20121605227) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3564841 + ... + 3570480.

It is an arithmetic number, because the mean of its divisors is an integer number (1198734096).

Almost surely, 2^20121605220 is an apocalyptic number.

20121605220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20121605220 is an abundant number, since it is smaller than the sum of its proper divisors (37417631388).

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

20121605220 is a wasteful number, since it uses less digits than its factorization.

20121605220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7135380 (or 7135378 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The spelling of 20121605220 in words is "twenty billion, one hundred twenty-one million, six hundred five thousand, two hundred twenty".