18954673921 has 4 divisors (see below), whose sum is σ = 19312309332. Its totient is φ = 18597038512.

The previous prime is 18954673861. The next prime is 18954673951. The reversal of 18954673921 is 12937645981.

It is a happy number.

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 7693219521 + 11261454400 = 87711^2 + 106120^2 .

It is a cyclic number.

It is not a de Polignac number, because 18954673921 - 2³¹ = 16807190273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18954673951) 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, 178817626 + ... + 178817731.

It is an arithmetic number, because the mean of its divisors is an integer number (4828077333).

Almost surely, 2^18954673921 is an apocalyptic number.

It is an amenable number.

18954673921 is a deficient number, since it is larger than the sum of its proper divisors (357635411).

18954673921 is an equidigital number, since it uses as much as digits as its factorization.

18954673921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357635410.

The product of its digits is 3265920, while the sum is 55.

The spelling of 18954673921 in words is "eighteen billion, nine hundred fifty-four million, six hundred seventy-three thousand, nine hundred twenty-one".