81047949 has 8 divisors (see below), whose sum is σ = 108300192. Its totient is φ = 53913840.

The previous prime is 81047933. The next prime is 81047951. The reversal of 81047949 is 94974018.

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

It is not a de Polignac number, because 81047949 - 2⁴ = 81047933 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81047949.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81047149) 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, 27919 + ... + 30684.

It is an arithmetic number, because the mean of its divisors is an integer number (13537524).

Almost surely, 2^81047949 is an apocalyptic number.

It is an amenable number.

81047949 is a deficient number, since it is larger than the sum of its proper divisors (27252243).

81047949 is a wasteful number, since it uses less digits than its factorization.

81047949 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59067.

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 81047949 is about 9002.6634392273. The cubic root of 81047949 is about 432.7602300842.

The spelling of 81047949 in words is "eighty-one million, forty-seven thousand, nine hundred forty-nine".