81739197 has 48 divisors (see below), whose sum is σ = 131414400. Its totient is φ = 48746880.

The previous prime is 81739187. The next prime is 81739201. The reversal of 81739197 is 79193718.

It is not a de Polignac number, because 81739197 - 2⁷ = 81739069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81739187) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 262672 + ... + 262982.

It is an arithmetic number, because the mean of its divisors is an integer number (2737800).

Almost surely, 2^81739197 is an apocalyptic number.

81739197 is a gapful number since it is divisible by the number (87) formed by its first and last digit.

It is an amenable number.

81739197 is a deficient number, since it is larger than the sum of its proper divisors (49675203).

81739197 is a wasteful number, since it uses less digits than its factorization.

81739197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 418 (or 415 counting only the distinct ones).

The product of its digits is 95256, while the sum is 45.

The square root of 81739197 is about 9040.9732330098. The cubic root of 81739197 is about 433.9870684276.

The spelling of 81739197 in words is "eighty-one million, seven hundred thirty-nine thousand, one hundred ninety-seven".