221818182020 has 24 divisors (see below), whose sum is σ = 465871719768. Its totient is φ = 88717075200.

The previous prime is 221818182017. The next prime is 221818182043. The reversal of 221818182020 is 20281818122.

It can be written as a sum of positive squares in 4 ways, for example, as 10115129476 + 211703052544 = 100574^2 + 460112^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 457751 + ... + 808190.

It is an arithmetic number, because the mean of its divisors is an integer number (19411321657).

Almost surely, 2^221818182020 is an apocalyptic number.

221818182020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221818182020 is an abundant number, since it is smaller than the sum of its proper divisors (244053537748).

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

221818182020 is a wasteful number, since it uses less digits than its factorization.

221818182020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1274711 (or 1274709 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 35.

The spelling of 221818182020 in words is "two hundred twenty-one billion, eight hundred eighteen million, one hundred eighty-two thousand, twenty".