1209978639 has 24 divisors (see below), whose sum is σ = 1807183872. Its totient is φ = 779308560.

The previous prime is 1209978619. The next prime is 1209978673. The reversal of 1209978639 is 9368799021.

It is not a de Polignac number, because 1209978639 - 2⁵ = 1209978607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1209978619) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 177162 + ... + 183864.

It is an arithmetic number, because the mean of its divisors is an integer number (75299328).

Almost surely, 2^1209978639 is an apocalyptic number.

1209978639 is a deficient number, since it is larger than the sum of its proper divisors (597205233).

1209978639 is a wasteful number, since it uses less digits than its factorization.

1209978639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7387 (or 7384 counting only the distinct ones).

The product of its (nonzero) digits is 1469664, while the sum is 54.

The square root of 1209978639 is about 34784.7472177102. The cubic root of 1209978639 is about 1065.5959661156.

The spelling of 1209978639 in words is "one billion, two hundred nine million, nine hundred seventy-eight thousand, six hundred thirty-nine".