18645947 has 4 divisors (see below), whose sum is σ = 18962040. Its totient is φ = 18329856.

The previous prime is 18645941. The next prime is 18645953. The reversal of 18645947 is 74954681.

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

It is an interprime number because it is at equal distance from previous prime (18645941) and next prime (18645953).

It is a cyclic number.

It is not a de Polignac number, because 18645947 - 2⁶ = 18645883 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18645898 and 18645907.

It is not an unprimeable number, because it can be changed into a prime (18645941) 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, 157958 + ... + 158075.

It is an arithmetic number, because the mean of its divisors is an integer number (4740510).

Almost surely, 2^18645947 is an apocalyptic number.

18645947 is a deficient number, since it is larger than the sum of its proper divisors (316093).

18645947 is an equidigital number, since it uses as much as digits as its factorization.

18645947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316092.

The product of its digits is 241920, while the sum is 44.

The square root of 18645947 is about 4318.0952976978. The cubic root of 18645947 is about 265.1722956909.

The spelling of 18645947 in words is "eighteen million, six hundred forty-five thousand, nine hundred forty-seven".