81340645 has 16 divisors (see below), whose sum is σ = 100264320. Its totient is φ = 63324864.

The previous prime is 81340619. The next prime is 81340657. The reversal of 81340645 is 54604318.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 81340645 - 2⁷ = 81340517 is a prime.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 29047 + ... + 31723.

It is an arithmetic number, because the mean of its divisors is an integer number (6266520).

Almost surely, 2^81340645 is an apocalyptic number.

It is an amenable number.

81340645 is a deficient number, since it is larger than the sum of its proper divisors (18923675).

81340645 is a wasteful number, since it uses less digits than its factorization.

81340645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2844.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 81340645 is about 9018.9048670002. The cubic root of 81340645 is about 433.2805599770.

It can be divided in two parts, 813 and 40645, that multiplied together give a triangular number (33044385 = T₈₁₂₉).

The spelling of 81340645 in words is "eighty-one million, three hundred forty thousand, six hundred forty-five".