81187037 has 8 divisors (see below), whose sum is σ = 84146040. Its totient is φ = 78238720.

The previous prime is 81187021. The next prime is 81187063. The reversal of 81187037 is 73078118.

It can be written as a sum of positive squares in 4 ways, for example, as 17522596 + 63664441 = 4186^2 + 7979^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81187037 - 2⁴ = 81187021 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81186988 and 81187006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81187097) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14837 + ... + 19557.

It is an arithmetic number, because the mean of its divisors is an integer number (10518255).

Almost surely, 2^81187037 is an apocalyptic number.

It is an amenable number.

81187037 is a deficient number, since it is larger than the sum of its proper divisors (2959003).

81187037 is a wasteful number, since it uses less digits than its factorization.

81187037 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5343.

The product of its (nonzero) digits is 9408, while the sum is 35.

The square root of 81187037 is about 9010.3849529307. The cubic root of 81187037 is about 433.0076447580.

The spelling of 81187037 in words is "eighty-one million, one hundred eighty-seven thousand, thirty-seven".