1290639138 has 8 divisors (see below), whose sum is σ = 2581278288. Its totient is φ = 430213044.

The previous prime is 1290639137. The next prime is 1290639169. The reversal of 1290639138 is 8319360921.

1290639138 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

1290639138 is an admirable number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1290639138.

It is not an unprimeable number, because it can be changed into a prime (1290639137) 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, 107553256 + ... + 107553267.

It is an arithmetic number, because the mean of its divisors is an integer number (322659786).

Almost surely, 2^1290639138 is an apocalyptic number.

1290639138 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1290639138 is a wasteful number, since it uses less digits than its factorization.

1290639138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215106528.

The product of its (nonzero) digits is 69984, while the sum is 42.

The square root of 1290639138 is about 35925.4664270347. The cubic root of 1290639138 is about 1088.7669860610.

The spelling of 1290639138 in words is "one billion, two hundred ninety million, six hundred thirty-nine thousand, one hundred thirty-eight".