1289738639 has 16 divisors (see below), whose sum is σ = 1619028480. Its totient is φ = 1001769120.

The previous prime is 1289738627. The next prime is 1289738657. The reversal of 1289738639 is 9368379821.

It is a cyclic number.

It is not a de Polignac number, because 1289738639 - 2²⁰ = 1288690063 is a prime.

It is a super-3 number, since 3×1289738639³ (a number of 28 digits) contains 333 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 (1289738699) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 207752 + ... + 213869.

It is an arithmetic number, because the mean of its divisors is an integer number (101189280).

Almost surely, 2^1289738639 is an apocalyptic number.

1289738639 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

1289738639 is a deficient number, since it is larger than the sum of its proper divisors (329289841).

1289738639 is a wasteful number, since it uses less digits than its factorization.

1289738639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421670.

The product of its digits is 3919104, while the sum is 56.

The square root of 1289738639 is about 35912.9313618368. The cubic root of 1289738639 is about 1088.5137105938.

The spelling of 1289738639 in words is "one billion, two hundred eighty-nine million, seven hundred thirty-eight thousand, six hundred thirty-nine".