81291206 has 8 divisors (see below), whose sum is σ = 122056200. Its totient is φ = 40605808.

The previous prime is 81291193. The next prime is 81291209. The reversal of 81291206 is 60219218.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81291209) 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, 17276 + ... + 21471.

It is an arithmetic number, because the mean of its divisors is an integer number (15257025).

Almost surely, 2^81291206 is an apocalyptic number.

81291206 is a deficient number, since it is larger than the sum of its proper divisors (40764994).

81291206 is a wasteful number, since it uses less digits than its factorization.

81291206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39798.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 81291206 is about 9016.1635965637. The cubic root of 81291206 is about 433.1927592677.

The spelling of 81291206 in words is "eighty-one million, two hundred ninety-one thousand, two hundred six".