81948729 has 8 divisors (see below), whose sum is σ = 115015840. Its totient is φ = 51757056.

The previous prime is 81948677. The next prime is 81948731. The reversal of 81948729 is 92784918.

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

It is not a de Polignac number, because 81948729 - 2²⁰ = 80900153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81948749) 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, 718792 + ... + 718905.

It is an arithmetic number, because the mean of its divisors is an integer number (14376980).

Almost surely, 2^81948729 is an apocalyptic number.

It is an amenable number.

81948729 is a deficient number, since it is larger than the sum of its proper divisors (33067111).

81948729 is a wasteful number, since it uses less digits than its factorization.

81948729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1437719.

The product of its digits is 290304, while the sum is 48.

The square root of 81948729 is about 9052.5537280924. The cubic root of 81948729 is about 434.3575825806.

The spelling of 81948729 in words is "eighty-one million, nine hundred forty-eight thousand, seven hundred twenty-nine".