1638851139 has 24 divisors (see below), whose sum is σ = 2431119600. Its totient is φ = 1063215360.

The previous prime is 1638851117. The next prime is 1638851141. The reversal of 1638851139 is 9311588361.

It is a happy number.

1638851139 is a `hidden beast` number, since 1 + 638 + 8 + 5 + 1 + 1 + 3 + 9 = 666.

It is not a de Polignac number, because 1638851139 - 2²⁴ = 1622073923 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1638851094 and 1638851103.

It is not an unprimeable number, because it can be changed into a prime (1638851639) 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, 145492 + ... + 156350.

It is an arithmetic number, because the mean of its divisors is an integer number (101296650).

Almost surely, 2^1638851139 is an apocalyptic number.

1638851139 is a deficient number, since it is larger than the sum of its proper divisors (792268461).

1638851139 is a wasteful number, since it uses less digits than its factorization.

1638851139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11315 (or 11312 counting only the distinct ones).

The product of its digits is 155520, while the sum is 45.

The square root of 1638851139 is about 40482.7264274530. The cubic root of 1638851139 is about 1178.9982734297.

The spelling of 1638851139 in words is "one billion, six hundred thirty-eight million, eight hundred fifty-one thousand, one hundred thirty-nine".