1638000481 has 4 divisors (see below), whose sum is σ = 1764000532. Its totient is φ = 1512000432.

The previous prime is 1638000437. The next prime is 1638000493. The reversal of 1638000481 is 1840008361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1840008361 = 787 ⋅2338003.

It can be written as a sum of positive squares in 2 ways, for example, as 378886225 + 1259114256 = 19465^2 + 35484^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638000481 - 2²¹ = 1635903329 is a prime.

It is a super-2 number, since 2×1638000481² = 5366091151512462722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1638000281) 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, 63000006 + ... + 63000031.

It is an arithmetic number, because the mean of its divisors is an integer number (441000133).

Almost surely, 2^1638000481 is an apocalyptic number.

It is an amenable number.

1638000481 is a deficient number, since it is larger than the sum of its proper divisors (126000051).

1638000481 is a wasteful number, since it uses less digits than its factorization.

1638000481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126000050.

The product of its (nonzero) digits is 4608, while the sum is 31.

The square root of 1638000481 is about 40472.2186320444. The cubic root of 1638000481 is about 1178.7942488207.

The spelling of 1638000481 in words is "one billion, six hundred thirty-eight million, four hundred eighty-one", and thus it is an aban number.