2165640440 has 32 divisors (see below), whose sum is σ = 5084549280. Its totient is φ = 828592512.

The previous prime is 2165640431. The next prime is 2165640461. The reversal of 2165640440 is 440465612.

It is a junction number, because it is equal to n+sod(n) for n = 2165640397 and 2165640406.

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, 1176059 + ... + 1177898.

It is an arithmetic number, because the mean of its divisors is an integer number (158892165).

Almost surely, 2^2165640440 is an apocalyptic number.

2165640440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2165640440 is an abundant number, since it is smaller than the sum of its proper divisors (2918908840).

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

2165640440 is a wasteful number, since it uses less digits than its factorization.

2165640440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2353991 (or 2353987 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

The square root of 2165640440 is about 46536.4420642576. The cubic root of 2165640440 is about 1293.7850174812.

The spelling of 2165640440 in words is "two billion, one hundred sixty-five million, six hundred forty thousand, four hundred forty".