18165961 has 16 divisors (see below), whose sum is σ = 20357568. Its totient is φ = 16072000.

The previous prime is 18165949. The next prime is 18165967. The reversal of 18165961 is 16956181.

It is a cyclic number.

It is not a de Polignac number, because 18165961 - 2⁹ = 18165449 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18165961.

It is not an unprimeable number, because it can be changed into a prime (18165967) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 92115 + ... + 92311.

It is an arithmetic number, because the mean of its divisors is an integer number (1272348).

Almost surely, 2^18165961 is an apocalyptic number.

18165961 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18165961 is a deficient number, since it is larger than the sum of its proper divisors (2191607).

18165961 is a wasteful number, since it uses less digits than its factorization.

18165961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392.

The product of its digits is 12960, while the sum is 37.

The square root of 18165961 is about 4262.1545021268. The cubic root of 18165961 is about 262.8771226458.

It can be divided in two parts, 1816 and 5961, that added together give a palindrome (7777).

The spelling of 18165961 in words is "eighteen million, one hundred sixty-five thousand, nine hundred sixty-one".