18978007 has 4 divisors (see below), whose sum is σ = 19419400. Its totient is φ = 18536616.

The previous prime is 18977963. The next prime is 18978019. The reversal of 18978007 is 70087981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70087981 = 109 ⋅643009.

It is a cyclic number.

It is not a de Polignac number, because 18978007 - 2⁷ = 18977879 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 (18978067) 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, 220632 + ... + 220717.

It is an arithmetic number, because the mean of its divisors is an integer number (4854850).

Almost surely, 2^18978007 is an apocalyptic number.

18978007 is a deficient number, since it is larger than the sum of its proper divisors (441393).

18978007 is an equidigital number, since it uses as much as digits as its factorization.

18978007 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 441392.

The product of its (nonzero) digits is 28224, while the sum is 40.

The square root of 18978007 is about 4356.3754429571. The cubic root of 18978007 is about 266.7371669500.

The spelling of 18978007 in words is "eighteen million, nine hundred seventy-eight thousand, seven".