259640639 has 4 divisors (see below), whose sum is σ = 260411424. Its totient is φ = 258869856.

The previous prime is 259640621. The next prime is 259640663. The reversal of 259640639 is 936046952.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 259640639 - 2¹⁶ = 259575103 is a prime.

It is a super-2 number, since 2×259640639² = 134826522840656642, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 259640639.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (259640669) 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, 384887 + ... + 385560.

It is an arithmetic number, because the mean of its divisors is an integer number (65102856).

Almost surely, 2^259640639 is an apocalyptic number.

259640639 is a deficient number, since it is larger than the sum of its proper divisors (770785).

259640639 is an equidigital number, since it uses as much as digits as its factorization.

259640639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 770784.

The product of its (nonzero) digits is 349920, while the sum is 44.

The square root of 259640639 is about 16113.3683319162. The cubic root of 259640639 is about 637.9562400583.

The spelling of 259640639 in words is "two hundred fifty-nine million, six hundred forty thousand, six hundred thirty-nine".