2111781620 has 24 divisors (see below), whose sum is σ = 4775875944. Its totient is φ = 779734656.

The previous prime is 2111781611. The next prime is 2111781673. The reversal of 2111781620 is 261871112.

It can be written as a sum of positive squares in 4 ways, for example, as 6990736 + 2104790884 = 2644^2 + 45878^2 .

It is a super-2 number, since 2×2111781620² = 8919243221139648800, which contains 22 as substring.

It is a congruent number.

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, 4060859 + ... + 4061378.

It is an arithmetic number, because the mean of its divisors is an integer number (198994831).

Almost surely, 2^2111781620 is an apocalyptic number.

2111781620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2111781620 is an abundant number, since it is smaller than the sum of its proper divisors (2664094324).

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

2111781620 is a wasteful number, since it uses less digits than its factorization.

2111781620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8122259 (or 8122257 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 2111781620 is about 45954.1251684764. The cubic root of 2111781620 is about 1282.9695094295.

The spelling of 2111781620 in words is "two billion, one hundred eleven million, seven hundred eighty-one thousand, six hundred twenty".