812181537 has 6 divisors (see below), whose sum is σ = 1173151122. Its totient is φ = 541454352.

The previous prime is 812181527. The next prime is 812181547. The reversal of 812181537 is 735181218.

It is an interprime number because it is at equal distance from previous prime (812181527) and next prime (812181547).

It can be written as a sum of positive squares in only one way, i.e., 424524816 + 387656721 = 20604^2 + 19689^2 .

It is not a de Polignac number, because 812181537 - 2⁴ = 812181521 is a prime.

It is not an unprimeable number, because it can be changed into a prime (812181527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 45121188 + ... + 45121205.

It is an arithmetic number, because the mean of its divisors is an integer number (195525187).

Almost surely, 2^812181537 is an apocalyptic number.

It is an amenable number.

812181537 is a deficient number, since it is larger than the sum of its proper divisors (360969585).

812181537 is a wasteful number, since it uses less digits than its factorization.

812181537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90242399 (or 90242396 counting only the distinct ones).

The product of its digits is 13440, while the sum is 36.

The square root of 812181537 is about 28498.7988694261. The cubic root of 812181537 is about 933.0058587391.

The spelling of 812181537 in words is "eight hundred twelve million, one hundred eighty-one thousand, five hundred thirty-seven".