18561937 has 4 divisors (see below), whose sum is σ = 18732340. Its totient is φ = 18391536.

The previous prime is 18561923. The next prime is 18561941. The reversal of 18561937 is 73916581.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73916581 = 1213 ⋅60937.

It can be written as a sum of positive squares in 2 ways, for example, as 5716881 + 12845056 = 2391^2 + 3584^2 .

It is a cyclic number.

It is not a de Polignac number, because 18561937 - 2¹¹ = 18559889 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18561937.

It is not an unprimeable number, because it can be changed into a prime (18561967) 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 3 ways as a sum of consecutive naturals, for example, 85038 + ... + 85255.

It is an arithmetic number, because the mean of its divisors is an integer number (4683085).

Almost surely, 2^18561937 is an apocalyptic number.

It is an amenable number.

18561937 is a deficient number, since it is larger than the sum of its proper divisors (170403).

18561937 is a wasteful number, since it uses less digits than its factorization.

18561937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170402.

The product of its digits is 45360, while the sum is 40.

The square root of 18561937 is about 4308.3566472612. The cubic root of 18561937 is about 264.7734482387.

The spelling of 18561937 in words is "eighteen million, five hundred sixty-one thousand, nine hundred thirty-seven".