1638127345 has 4 divisors (see below), whose sum is σ = 1965752820. Its totient is φ = 1310501872.

The previous prime is 1638127333. The next prime is 1638127363. The reversal of 1638127345 is 5437218361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5437218361 = 127 ⋅42812743.

It can be written as a sum of positive squares in 2 ways, for example, as 796199089 + 841928256 = 28217^2 + 29016^2 .

It is a cyclic number.

It is not a de Polignac number, because 1638127345 - 2⁷ = 1638127217 is a prime.

It is a super-2 number, since 2×1638127345² = 5366922396873498050, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1638127298 and 1638127307.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163812730 + ... + 163812739.

It is an arithmetic number, because the mean of its divisors is an integer number (491438205).

Almost surely, 2^1638127345 is an apocalyptic number.

It is an amenable number.

1638127345 is a deficient number, since it is larger than the sum of its proper divisors (327625475).

1638127345 is an equidigital number, since it uses as much as digits as its factorization.

1638127345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327625474.

The product of its digits is 120960, while the sum is 40.

The square root of 1638127345 is about 40473.7858990236. The cubic root of 1638127345 is about 1178.8246807802.

The spelling of 1638127345 in words is "one billion, six hundred thirty-eight million, one hundred twenty-seven thousand, three hundred forty-five".