81109437 has 4 divisors (see below), whose sum is σ = 108145920. Its totient is φ = 54072956.

The previous prime is 81109429. The next prime is 81109447. The reversal of 81109437 is 73490118.

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 81109437 - 2³ = 81109429 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81109398 and 81109407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81109417) 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, 13518237 + ... + 13518242.

It is an arithmetic number, because the mean of its divisors is an integer number (27036480).

Almost surely, 2^81109437 is an apocalyptic number.

It is an amenable number.

81109437 is a deficient number, since it is larger than the sum of its proper divisors (27036483).

81109437 is a wasteful number, since it uses less digits than its factorization.

81109437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27036482.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 81109437 is about 9006.0777811431. The cubic root of 81109437 is about 432.8696420022.

The spelling of 81109437 in words is "eighty-one million, one hundred nine thousand, four hundred thirty-seven".