2181139785 has 32 divisors (see below), whose sum is σ = 4230092160. Its totient is φ = 1057521600.

The previous prime is 2181139781. The next prime is 2181139817. The reversal of 2181139785 is 5879311812.

2181139785 is a `hidden beast` number, since 2 + 181 + 1 + 397 + 85 = 666.

It is not a de Polignac number, because 2181139785 - 2² = 2181139781 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 2181139785.

It is not an unprimeable number, because it can be changed into a prime (2181139781) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 732906 + ... + 735875.

It is an arithmetic number, because the mean of its divisors is an integer number (132190380).

Almost surely, 2^2181139785 is an apocalyptic number.

It is an amenable number.

2181139785 is a deficient number, since it is larger than the sum of its proper divisors (2048952375).

2181139785 is a wasteful number, since it uses less digits than its factorization.

2181139785 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1468806 (or 1468800 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The square root of 2181139785 is about 46702.6742810302. The cubic root of 2181139785 is about 1296.8641944888.

The spelling of 2181139785 in words is "two billion, one hundred eighty-one million, one hundred thirty-nine thousand, seven hundred eighty-five".