1821738636 has 36 divisors (see below), whose sum is σ = 4607736952. Its totient is φ = 606878784.

The previous prime is 1821738629. The next prime is 1821738641. The reversal of 1821738636 is 6368371281.

1821738636 is a `hidden beast` number, since 1 + 8 + 2 + 1 + 7 + 3 + 8 + 636 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a junction number, because it is equal to n+sod(n) for n = 1821738591 and 1821738600.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 48675 + ... + 77541.

Almost surely, 2^1821738636 is an apocalyptic number.

It is an amenable number.

1821738636 is an abundant number, since it is smaller than the sum of its proper divisors (2785998316).

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

1821738636 is a wasteful number, since it uses less digits than its factorization.

1821738636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30630 (or 30625 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 1821738636 is about 42681.8302794058. The cubic root of 1821738636 is about 1221.3178083147.

The spelling of 1821738636 in words is "one billion, eight hundred twenty-one million, seven hundred thirty-eight thousand, six hundred thirty-six".