2155991040 has 416 divisors, whose sum is σ = 8775509760. Its totient is φ = 491913216.

The previous prime is 2155991023. The next prime is 2155991107. The reversal of 2155991040 is 401995512.

2155991040 is a `hidden beast` number, since 2 + 15 + 599 + 10 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 2155990986 and 2155991004.

It is a congruent number.

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, 3870442 + ... + 3870998.

Almost surely, 2^2155991040 is an apocalyptic number.

2155991040 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 2155991040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4387754880).

2155991040 is an abundant number, since it is smaller than the sum of its proper divisors (6619518720).

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

2155991040 is an equidigital number, since it uses as much as digits as its factorization.

2155991040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602 (or 574 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 36.

The square root of 2155991040 is about 46432.6505812451. The cubic root of 2155991040 is about 1291.8605925875.

The spelling of 2155991040 in words is "two billion, one hundred fifty-five million, nine hundred ninety-one thousand, forty".