1813431636 has 18 divisors (see below), whose sum is σ = 4583952282. Its totient is φ = 604477200.

The previous prime is 1813431629. The next prime is 1813431671. The reversal of 1813431636 is 6361343181.

1813431636 is a `hidden beast` number, since 1 + 8 + 13 + 4 + 3 + 1 + 636 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1555829136 + 257602500 = 39444^2 + 16050^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 50373101 = 1813431636 / (1 + 8 + 1 + 3 + 4 + 3 + 1 + 6 + 3 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 1813431636.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25186515 + ... + 25186586.

Almost surely, 2^1813431636 is an apocalyptic number.

It is an amenable number.

1813431636 is an abundant number, since it is smaller than the sum of its proper divisors (2770520646).

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

1813431636 is a wasteful number, since it uses less digits than its factorization.

1813431636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50373111 (or 50373106 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 1813431636 is about 42584.4060191052. The cubic root of 1813431636 is about 1219.4586050752.

It can be divided in two parts, 18134 and 31636, that added together give a triangular number (49770 = T₃₁₅).

The spelling of 1813431636 in words is "one billion, eight hundred thirteen million, four hundred thirty-one thousand, six hundred thirty-six".