18991036 has 24 divisors (see below), whose sum is σ = 34849584. Its totient is φ = 9045120.

The previous prime is 18991033. The next prime is 18991039. The reversal of 18991036 is 63019981.

It is an interprime number because it is at equal distance from previous prime (18991033) and next prime (18991039).

It is a junction number, because it is equal to n+sod(n) for n = 18990986 and 18991004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18991033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5706 + ... + 8398.

It is an arithmetic number, because the mean of its divisors is an integer number (1452066).

Almost surely, 2^18991036 is an apocalyptic number.

It is an amenable number.

18991036 is a deficient number, since it is larger than the sum of its proper divisors (15858548).

18991036 is a wasteful number, since it uses less digits than its factorization.

18991036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2781 (or 2779 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 18991036 is about 4357.8705809145. The cubic root of 18991036 is about 266.7981941441.

The spelling of 18991036 in words is "eighteen million, nine hundred ninety-one thousand, thirty-six".