1361991138 has 64 divisors (see below), whose sum is σ = 2989965312. Its totient is φ = 412251840.

The previous prime is 1361991121. The next prime is 1361991139. The reversal of 1361991138 is 8311991631.

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 1361991138.

It is not an unprimeable number, because it can be changed into a prime (1361991139) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 223731 + ... + 229737.

It is an arithmetic number, because the mean of its divisors is an integer number (46718208).

Almost surely, 2^1361991138 is an apocalyptic number.

1361991138 is an abundant number, since it is smaller than the sum of its proper divisors (1627974174).

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

1361991138 is a wasteful number, since it uses less digits than its factorization.

1361991138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6119.

The product of its digits is 34992, while the sum is 42.

The square root of 1361991138 is about 36905.1641101892. The cubic root of 1361991138 is about 1108.4720849500.

The spelling of 1361991138 in words is "one billion, three hundred sixty-one million, nine hundred ninety-one thousand, one hundred thirty-eight".