81647377 has 8 divisors (see below), whose sum is σ = 95216000. Its totient is φ = 69983172.

The previous prime is 81647333. The next prime is 81647387. The reversal of 81647377 is 77374618.

It is not a de Polignac number, because 81647377 - 2¹⁵ = 81614609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81647387) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 118677 + ... + 119362.

It is an arithmetic number, because the mean of its divisors is an integer number (11902000).

Almost surely, 2^81647377 is an apocalyptic number.

It is an amenable number.

81647377 is a deficient number, since it is larger than the sum of its proper divisors (13568623).

81647377 is an equidigital number, since it uses as much as digits as its factorization.

81647377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238060 (or 238046 counting only the distinct ones).

The product of its digits is 197568, while the sum is 43.

The square root of 81647377 is about 9035.8938130104. The cubic root of 81647377 is about 433.8245041400.

The spelling of 81647377 in words is "eighty-one million, six hundred forty-seven thousand, three hundred seventy-seven".