202109111820 has 864 divisors, whose sum is σ = 806592923136. Its totient is φ = 41318553600.

The previous prime is 202109111803. The next prime is 202109111821. The reversal of 202109111820 is 28111901202.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (202109111821) by changing a digit.

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 287 ways as a sum of consecutive naturals, for example, 838626900 + ... + 838627140.

It is an arithmetic number, because the mean of its divisors is an integer number (933556624).

Almost surely, 2^202109111820 is an apocalyptic number.

202109111820 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 202109111820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (403296461568).

202109111820 is an abundant number, since it is smaller than the sum of its proper divisors (604483811316).

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

202109111820 is a wasteful number, since it uses less digits than its factorization.

202109111820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 375 (or 352 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The spelling of 202109111820 in words is "two hundred two billion, one hundred nine million, one hundred eleven thousand, eight hundred twenty".