1640642289 has 32 divisors (see below), whose sum is σ = 2572674048. Its totient is φ = 916872000.

The previous prime is 1640642251. The next prime is 1640642291. The reversal of 1640642289 is 9822460461.

1640642289 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1640642289 - 2⁷ = 1640642161 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1640642289.

It is not an unprimeable number, because it can be changed into a prime (1640642209) 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, 646954 + ... + 649484.

It is an arithmetic number, because the mean of its divisors is an integer number (80396064).

Almost surely, 2^1640642289 is an apocalyptic number.

It is an amenable number.

1640642289 is a deficient number, since it is larger than the sum of its proper divisors (932031759).

1640642289 is a wasteful number, since it uses less digits than its factorization.

1640642289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4069.

The product of its (nonzero) digits is 165888, while the sum is 42.

The square root of 1640642289 is about 40504.8427845363. The cubic root of 1640642289 is about 1179.4276380086.

The spelling of 1640642289 in words is "one billion, six hundred forty million, six hundred forty-two thousand, two hundred eighty-nine".