18436993 has 8 divisors (see below), whose sum is σ = 19814112. Its totient is φ = 17092416.

The previous prime is 18436987. The next prime is 18437021. The reversal of 18436993 is 39963481.

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 18436993 - 2¹³ = 18428801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18436903) 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, 6955 + ... + 9232.

It is an arithmetic number, because the mean of its divisors is an integer number (2476764).

Almost surely, 2^18436993 is an apocalyptic number.

It is an amenable number.

18436993 is a deficient number, since it is larger than the sum of its proper divisors (1377119).

18436993 is a wasteful number, since it uses less digits than its factorization.

18436993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16271.

The product of its digits is 139968, while the sum is 43.

The square root of 18436993 is about 4293.8319715611. The cubic root of 18436993 is about 264.1780297876.

It can be divided in two parts, 1843 and 6993, that added together give a square (8836 = 94²).

The spelling of 18436993 in words is "eighteen million, four hundred thirty-six thousand, nine hundred ninety-three".