81199413 has 12 divisors (see below), whose sum is σ = 117519948. Its totient is φ = 54025920.

The previous prime is 81199403. The next prime is 81199451. The reversal of 81199413 is 31499118.

It can be written as a sum of positive squares in 2 ways, for example, as 47361924 + 33837489 = 6882^2 + 5817^2 .

It is not a de Polignac number, because 81199413 - 2⁴ = 81199397 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81199403) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3970 + ... + 13347.

It is an arithmetic number, because the mean of its divisors is an integer number (9793329).

Almost surely, 2^81199413 is an apocalyptic number.

It is an amenable number.

81199413 is a deficient number, since it is larger than the sum of its proper divisors (36320535).

81199413 is a wasteful number, since it uses less digits than its factorization.

81199413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17844 (or 17841 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 81199413 is about 9011.0716898713. The cubic root of 81199413 is about 433.0296459318.

The spelling of 81199413 in words is "eighty-one million, one hundred ninety-nine thousand, four hundred thirteen".