38491813 has 4 divisors (see below), whose sum is σ = 38520108. Its totient is φ = 38463520.

The previous prime is 38491799. The next prime is 38491819. The reversal of 38491813 is 31819483.

38491813 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31819483 = 137 ⋅232259.

It can be written as a sum of positive squares in 2 ways, for example, as 14265729 + 24226084 = 3777^2 + 4922^2 .

It is a cyclic number.

It is not a de Polignac number, because 38491813 - 2²⁵ = 4937381 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 (38491819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11998 + ... + 14863.

It is an arithmetic number, because the mean of its divisors is an integer number (9630027).

Almost surely, 2^38491813 is an apocalyptic number.

It is an amenable number.

38491813 is a deficient number, since it is larger than the sum of its proper divisors (28295).

38491813 is a wasteful number, since it uses less digits than its factorization.

38491813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28294.

The product of its digits is 20736, while the sum is 37.

The square root of 38491813 is about 6204.1770606584. The cubic root of 38491813 is about 337.6417343427.

It can be divided in two parts, 38491 and 813, that added together give a cube (39304 = 34³).

The spelling of 38491813 in words is "thirty-eight million, four hundred ninety-one thousand, eight hundred thirteen".