1638791131 has 8 divisors (see below), whose sum is σ = 1695852000. Its totient is φ = 1581767040.

The previous prime is 1638791117. The next prime is 1638791137. The reversal of 1638791131 is 1311978361.

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

It is a cyclic number.

It is not a de Polignac number, because 1638791131 - 2⁹ = 1638790619 is a prime.

It is a super-2 number, since 2×1638791131² = 5371272742088518322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1638791137) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106195 + ... + 120643.

It is an arithmetic number, because the mean of its divisors is an integer number (211981500).

Almost surely, 2^1638791131 is an apocalyptic number.

1638791131 is a deficient number, since it is larger than the sum of its proper divisors (57060869).

1638791131 is a wasteful number, since it uses less digits than its factorization.

1638791131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18389.

The product of its digits is 27216, while the sum is 40.

The square root of 1638791131 is about 40481.9852650534. The cubic root of 1638791131 is about 1178.9838832287.

The spelling of 1638791131 in words is "one billion, six hundred thirty-eight million, seven hundred ninety-one thousand, one hundred thirty-one".