18620993 has 4 divisors (see below), whose sum is σ = 18813060. Its totient is φ = 18428928.

The previous prime is 18620989. The next prime is 18620999. The reversal of 18620993 is 39902681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3659569 + 14961424 = 1913^2 + 3868^2 .

It is a cyclic number.

It is not a de Polignac number, because 18620993 - 2² = 18620989 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18620999) 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, 95888 + ... + 96081.

It is an arithmetic number, because the mean of its divisors is an integer number (4703265).

Almost surely, 2^18620993 is an apocalyptic number.

It is an amenable number.

18620993 is a deficient number, since it is larger than the sum of its proper divisors (192067).

18620993 is an equidigital number, since it uses as much as digits as its factorization.

18620993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192066.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 18620993 is about 4315.2048618808. The cubic root of 18620993 is about 265.0539489071.

The spelling of 18620993 in words is "eighteen million, six hundred twenty thousand, nine hundred ninety-three".