18091961 has 8 divisors (see below), whose sum is σ = 19989504. Its totient is φ = 16287040.

The previous prime is 18091939. The next prime is 18091963. The reversal of 18091961 is 16919081.

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 18091961 - 2¹⁰ = 18090937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18091963) 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, 22745 + ... + 23526.

It is an arithmetic number, because the mean of its divisors is an integer number (2498688).

Almost surely, 2^18091961 is an apocalyptic number.

It is an amenable number.

18091961 is a deficient number, since it is larger than the sum of its proper divisors (1897543).

18091961 is a wasteful number, since it uses less digits than its factorization.

18091961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46311.

The product of its (nonzero) digits is 3888, while the sum is 35.

The square root of 18091961 is about 4253.4645878390. The cubic root of 18091961 is about 262.5196889238.

The spelling of 18091961 in words is "eighteen million, ninety-one thousand, nine hundred sixty-one".