18781073 has 4 divisors (see below), whose sum is σ = 19885860. Its totient is φ = 17676288.

The previous prime is 18781069. The next prime is 18781097. The reversal of 18781073 is 37018781.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37018781 = 1129 ⋅32789.

It can be written as a sum of positive squares in 2 ways, for example, as 8133904 + 10647169 = 2852^2 + 3263^2 .

It is a cyclic number.

It is not a de Polignac number, because 18781073 - 2² = 18781069 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18781013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 552368 + ... + 552401.

It is an arithmetic number, because the mean of its divisors is an integer number (4971465).

Almost surely, 2^18781073 is an apocalyptic number.

It is an amenable number.

18781073 is a deficient number, since it is larger than the sum of its proper divisors (1104787).

18781073 is a wasteful number, since it uses less digits than its factorization.

18781073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1104786.

The product of its (nonzero) digits is 9408, while the sum is 35.

The square root of 18781073 is about 4333.7135346029. The cubic root of 18781073 is about 265.8113168110.

The spelling of 18781073 in words is "eighteen million, seven hundred eighty-one thousand, seventy-three".