18921007 has 6 divisors (see below), whose sum is σ = 22010208. Its totient is φ = 16217964.

The previous prime is 18920987. The next prime is 18921011. The reversal of 18921007 is 70012981.

It is not a de Polignac number, because 18921007 - 2⁷ = 18920879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18921047) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 193023 + ... + 193120.

It is an arithmetic number, because the mean of its divisors is an integer number (3668368).

Almost surely, 2^18921007 is an apocalyptic number.

18921007 is a deficient number, since it is larger than the sum of its proper divisors (3089201).

18921007 is an equidigital number, since it uses as much as digits as its factorization.

18921007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 386157 (or 386150 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 18921007 is about 4349.8283874194. The cubic root of 18921007 is about 266.4698528672.

Adding to 18921007 its reverse (70012981), we get a palindrome (88933988).

The spelling of 18921007 in words is "eighteen million, nine hundred twenty-one thousand, seven".