2166779940 has 96 divisors (see below), whose sum is σ = 6710350080. Its totient is φ = 518939136.

The previous prime is 2166779939. The next prime is 2166779959. The reversal of 2166779940 is 499776612.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8680 + ... + 66399.

It is an arithmetic number, because the mean of its divisors is an integer number (69899480).

Almost surely, 2^2166779940 is an apocalyptic number.

2166779940 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 2166779940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3355175040).

2166779940 is an abundant number, since it is smaller than the sum of its proper divisors (4543570140).

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

2166779940 is a wasteful number, since it uses less digits than its factorization.

2166779940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75141 (or 75139 counting only the distinct ones).

The product of its (nonzero) digits is 1143072, while the sum is 51.

The square root of 2166779940 is about 46548.6835474431. The cubic root of 2166779940 is about 1294.0118956374.

The spelling of 2166779940 in words is "two billion, one hundred sixty-six million, seven hundred seventy-nine thousand, nine hundred forty".