1640969785 has 32 divisors (see below), whose sum is σ = 2507178240. Its totient is φ = 1002855168.

The previous prime is 1640969767. The next prime is 1640969801. The reversal of 1640969785 is 5879690461.

It is not a de Polignac number, because 1640969785 - 2⁷ = 1640969657 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 48987 + ... + 75376.

It is an arithmetic number, because the mean of its divisors is an integer number (78349320).

Almost surely, 2^1640969785 is an apocalyptic number.

It is an amenable number.

1640969785 is a deficient number, since it is larger than the sum of its proper divisors (866208455).

1640969785 is a wasteful number, since it uses less digits than its factorization.

1640969785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124417.

The product of its (nonzero) digits is 3265920, while the sum is 55.

The square root of 1640969785 is about 40508.8852599032. The cubic root of 1640969785 is about 1179.5061097426.

The spelling of 1640969785 in words is "one billion, six hundred forty million, nine hundred sixty-nine thousand, seven hundred eighty-five".