81149737 has 4 divisors (see below), whose sum is σ = 81894340. Its totient is φ = 80405136.

The previous prime is 81149711. The next prime is 81149749. The reversal of 81149737 is 73794118.

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 21381376 + 59768361 = 4624^2 + 7731^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81149737 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81149737.

It is not an unprimeable number, because it can be changed into a prime (81141737) 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, 372138 + ... + 372355.

It is an arithmetic number, because the mean of its divisors is an integer number (20473585).

Almost surely, 2^81149737 is an apocalyptic number.

It is an amenable number.

81149737 is a deficient number, since it is larger than the sum of its proper divisors (744603).

81149737 is a wasteful number, since it uses less digits than its factorization.

81149737 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 744602.

The product of its digits is 42336, while the sum is 40.

The square root of 81149737 is about 9008.3148812639. The cubic root of 81149737 is about 432.9413219399.

The spelling of 81149737 in words is "eighty-one million, one hundred forty-nine thousand, seven hundred thirty-seven".