81612037 has 4 divisors (see below), whose sum is σ = 87889900. Its totient is φ = 75334176.

The previous prime is 81612001. The next prime is 81612059. The reversal of 81612037 is 73021618.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45239076 + 36372961 = 6726^2 + 6031^2 .

It is a cyclic number.

It is not a de Polignac number, because 81612037 - 2⁷ = 81611909 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81611996 and 81612014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81612137) 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 3 ways as a sum of consecutive naturals, for example, 3138912 + ... + 3138937.

It is an arithmetic number, because the mean of its divisors is an integer number (21972475).

Almost surely, 2^81612037 is an apocalyptic number.

It is an amenable number.

81612037 is a deficient number, since it is larger than the sum of its proper divisors (6277863).

81612037 is a wasteful number, since it uses less digits than its factorization.

81612037 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6277862.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 81612037 is about 9033.9380670890. The cubic root of 81612037 is about 433.7619033516.

The spelling of 81612037 in words is "eighty-one million, six hundred twelve thousand, thirty-seven".