1812601638 has 28 divisors (see below), whose sum is σ = 4076492148. Its totient is φ = 604200060.

The previous prime is 1812601633. The next prime is 1812601663. The reversal of 1812601638 is 8361062181.

1812601638 is a `hidden beast` number, since 1 + 8 + 12 + 6 + 0 + 1 + 638 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1812601631) 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 13 ways as a sum of consecutive naturals, for example, 620148 + ... + 623063.

Almost surely, 2^1812601638 is an apocalyptic number.

1812601638 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1812601638 is an abundant number, since it is smaller than the sum of its proper divisors (2263890510).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1812601638 is an equidigital number, since it uses as much as digits as its factorization.

1812601638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243231 (or 1243216 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 1812601638 is about 42574.6595758557. The cubic root of 1812601638 is about 1219.2725301145.

The spelling of 1812601638 in words is "one billion, eight hundred twelve million, six hundred one thousand, six hundred thirty-eight".