1816539637 has 4 divisors (see below), whose sum is σ = 1981679616. Its totient is φ = 1651399660.

The previous prime is 1816539623. The next prime is 1816539691. The reversal of 1816539637 is 7369356181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1816539637 - 2¹¹ = 1816537589 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1816539037) 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, 82569973 + ... + 82569994.

It is an arithmetic number, because the mean of its divisors is an integer number (495419904).

Almost surely, 2^1816539637 is an apocalyptic number.

It is an amenable number.

1816539637 is a deficient number, since it is larger than the sum of its proper divisors (165139979).

1816539637 is a wasteful number, since it uses less digits than its factorization.

1816539637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165139978.

The product of its digits is 816480, while the sum is 49.

The square root of 1816539637 is about 42620.8826398516. The cubic root of 1816539637 is about 1220.1548753037.

The spelling of 1816539637 in words is "one billion, eight hundred sixteen million, five hundred thirty-nine thousand, six hundred thirty-seven".