2005643639 has 4 divisors (see below), whose sum is σ = 2005738800. Its totient is φ = 2005548480.

The previous prime is 2005643621. The next prime is 2005643681. The reversal of 2005643639 is 9363465002.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2005643639 - 2¹⁶ = 2005578103 is a prime.

It is a super-2 number, since 2×2005643639² = 8045212813322324642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2005640639) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 314 + ... + 63335.

It is an arithmetic number, because the mean of its divisors is an integer number (501434700).

Almost surely, 2^2005643639 is an apocalyptic number.

2005643639 is a deficient number, since it is larger than the sum of its proper divisors (95161).

2005643639 is an equidigital number, since it uses as much as digits as its factorization.

2005643639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95160.

The product of its (nonzero) digits is 116640, while the sum is 38.

The square root of 2005643639 is about 44784.4129022588. The cubic root of 2005643639 is about 1261.1050268648.

The spelling of 2005643639 in words is "two billion, five million, six hundred forty-three thousand, six hundred thirty-nine".