18940637 has 4 divisors (see below), whose sum is σ = 19061436. Its totient is φ = 18819840.

The previous prime is 18940627. The next prime is 18940651. The reversal of 18940637 is 73604981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73604981 = 83 ⋅886807.

It can be written as a sum of positive squares in 2 ways, for example, as 10982596 + 7958041 = 3314^2 + 2821^2 .

It is a cyclic number.

It is not a de Polignac number, because 18940637 - 2⁶ = 18940573 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 18940637.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18940627) 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, 60164 + ... + 60477.

It is an arithmetic number, because the mean of its divisors is an integer number (4765359).

Almost surely, 2^18940637 is an apocalyptic number.

It is an amenable number.

18940637 is a deficient number, since it is larger than the sum of its proper divisors (120799).

18940637 is a wasteful number, since it uses less digits than its factorization.

18940637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120798.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 18940637 is about 4352.0842133396. The cubic root of 18940637 is about 266.5619726175.

The spelling of 18940637 in words is "eighteen million, nine hundred forty thousand, six hundred thirty-seven".