18473974561 has 9 divisors (see below), whose sum is σ = 21491240499. Its totient is φ = 15834019824.

The previous prime is 18473974537. The next prime is 18473974619. The reversal of 18473974561 is 16547937481.

The square root of 18473974561 is 135919.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 47541025 + 18426433536 = 6895^2 + 135744^2 .

It is not a de Polignac number, because 18473974561 - 2¹¹ = 18473972513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18473974261) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 941725 + ... + 961141.

It is an arithmetic number, because the mean of its divisors is an integer number (2387915611).

Almost surely, 2^18473974561 is an apocalyptic number.

18473974561 is the 135919-th square number.

18473974561 is the 67960-th centered octagonal number.

It is an amenable number.

18473974561 is a deficient number, since it is larger than the sum of its proper divisors (3017265938).

18473974561 is an frugal number, since it uses more digits than its factorization.

18473974561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38848 (or 19424 counting only the distinct ones).

The product of its digits is 5080320, while the sum is 55.

The spelling of 18473974561 in words is "eighteen billion, four hundred seventy-three million, nine hundred seventy-four thousand, five hundred sixty-one".