81693151 has 8 divisors (see below), whose sum is σ = 84285824. Its totient is φ = 79120800.

The previous prime is 81693113. The next prime is 81693173. The reversal of 81693151 is 15139618.

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

It is not a de Polignac number, because 81693151 - 2⁷ = 81693023 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81696151) 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 7 ways as a sum of consecutive naturals, for example, 3301 + ... + 13201.

It is an arithmetic number, because the mean of its divisors is an integer number (10535728).

Almost surely, 2^81693151 is an apocalyptic number.

81693151 is a deficient number, since it is larger than the sum of its proper divisors (2592673).

81693151 is a wasteful number, since it uses less digits than its factorization.

81693151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10161.

The product of its digits is 6480, while the sum is 34.

The square root of 81693151 is about 9038.4263563963. The cubic root of 81693151 is about 433.9055607265.

The spelling of 81693151 in words is "eighty-one million, six hundred ninety-three thousand, one hundred fifty-one".