81646395 has 16 divisors (see below), whose sum is σ = 131665920. Its totient is φ = 43200864.

The previous prime is 81646387. The next prime is 81646399. The reversal of 81646395 is 59364618.

It is not a de Polignac number, because 81646395 - 2³ = 81646387 is a prime.

It is a super-2 number, since 2×81646395² = 13332267632992050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81646399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19525 + ... + 23334.

It is an arithmetic number, because the mean of its divisors is an integer number (8229120).

Almost surely, 2^81646395 is an apocalyptic number.

81646395 is a deficient number, since it is larger than the sum of its proper divisors (50019525).

81646395 is a wasteful number, since it uses less digits than its factorization.

81646395 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42994.

The product of its digits is 155520, while the sum is 42.

The square root of 81646395 is about 9035.8394740057. The cubic root of 81646395 is about 433.8227648828.

The spelling of 81646395 in words is "eighty-one million, six hundred forty-six thousand, three hundred ninety-five".