81943654 has 16 divisors (see below), whose sum is σ = 135188928. Its totient is φ = 37014912.

The previous prime is 81943651. The next prime is 81943657. The reversal of 81943654 is 45634918.

It is an interprime number because it is at equal distance from previous prime (81943651) and next prime (81943657).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81943651) 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, 32307 + ... + 34750.

It is an arithmetic number, because the mean of its divisors is an integer number (8449308).

Almost surely, 2^81943654 is an apocalyptic number.

81943654 is a deficient number, since it is larger than the sum of its proper divisors (53245274).

81943654 is a wasteful number, since it uses less digits than its factorization.

81943654 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67119.

The product of its digits is 103680, while the sum is 40.

The square root of 81943654 is about 9052.2734161093. The cubic root of 81943654 is about 434.3486159569.

The spelling of 81943654 in words is "eighty-one million, nine hundred forty-three thousand, six hundred fifty-four".