2157780240 has 240 divisors, whose sum is σ = 9034886016. Its totient is φ = 448358400.

The previous prime is 2157780223. The next prime is 2157780307. The reversal of 2157780240 is 420877512.

2157780240 is a `hidden beast` number, since 2 + 1 + 577 + 80 + 2 + 4 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

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 = 2157780195 and 2157780204.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 35980 + ... + 74900.

Almost surely, 2^2157780240 is an apocalyptic number.

2157780240 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 2157780240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4517443008).

2157780240 is an abundant number, since it is smaller than the sum of its proper divisors (6877105776).

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

2157780240 is a wasteful number, since it uses less digits than its factorization.

2157780240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38958 (or 38949 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 36.

The square root of 2157780240 is about 46451.9132006422. The cubic root of 2157780240 is about 1292.2178541028.

The spelling of 2157780240 in words is "two billion, one hundred fifty-seven million, seven hundred eighty thousand, two hundred forty".