18439505426 has 4 divisors (see below), whose sum is σ = 27659258142. Its totient is φ = 9219752712.

The previous prime is 18439505389. The next prime is 18439505471. The reversal of 18439505426 is 62450593481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 62450593481 = 61 ⋅1023780221.

It can be written as a sum of positive squares in only one way, i.e., 16796419201 + 1643086225 = 129601^2 + 40535^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4609876355 + ... + 4609876358.

Almost surely, 2^18439505426 is an apocalyptic number.

18439505426 is a deficient number, since it is larger than the sum of its proper divisors (9219752716).

18439505426 is an equidigital number, since it uses as much as digits as its factorization.

18439505426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9219752715.

The product of its (nonzero) digits is 1036800, while the sum is 47.

The spelling of 18439505426 in words is "eighteen billion, four hundred thirty-nine million, five hundred five thousand, four hundred twenty-six".