18389974949 has 4 divisors (see below), whose sum is σ = 18396105900. Its totient is φ = 18383844000.

The previous prime is 18389974937. The next prime is 18389974951. The reversal of 18389974949 is 94947998381.

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 4424644324 + 13965330625 = 66518^2 + 118175^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18389974949 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 (18389974249) 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, 3060974 + ... + 3066975.

It is an arithmetic number, because the mean of its divisors is an integer number (4599026475).

Almost surely, 2^18389974949 is an apocalyptic number.

It is an amenable number.

18389974949 is a deficient number, since it is larger than the sum of its proper divisors (6130951).

18389974949 is an equidigital number, since it uses as much as digits as its factorization.

18389974949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6130950.

The product of its digits is 141087744, while the sum is 71.

The spelling of 18389974949 in words is "eighteen billion, three hundred eighty-nine million, nine hundred seventy-four thousand, nine hundred forty-nine".