81187937 has 8 divisors (see below), whose sum is σ = 86217696. Its totient is φ = 76186432.

The previous prime is 81187921. The next prime is 81187943. The reversal of 81187937 is 73978118.

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 81187937 - 2⁴ = 81187921 is a prime.

It is a super-2 number, since 2×81187937² = 13182962228631938, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81187237) 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 7 ways as a sum of consecutive naturals, for example, 983 + ... + 12780.

It is an arithmetic number, because the mean of its divisors is an integer number (10777212).

Almost surely, 2^81187937 is an apocalyptic number.

It is an amenable number.

81187937 is a deficient number, since it is larger than the sum of its proper divisors (5029759).

81187937 is a wasteful number, since it uses less digits than its factorization.

81187937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14127.

The product of its digits is 84672, while the sum is 44.

The square root of 81187937 is about 9010.4348951646. The cubic root of 81187937 is about 433.0092447894.

The spelling of 81187937 in words is "eighty-one million, one hundred eighty-seven thousand, nine hundred thirty-seven".