81705151 has 8 divisors (see below), whose sum is σ = 92206800. Its totient is φ = 71715840.

The previous prime is 81705133. The next prime is 81705157. The reversal of 81705151 is 15150718.

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

It is not a de Polignac number, because 81705151 - 2⁷ = 81705023 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 (81705157) 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, 127746 + ... + 128383.

It is an arithmetic number, because the mean of its divisors is an integer number (11525850).

Almost surely, 2^81705151 is an apocalyptic number.

81705151 is a deficient number, since it is larger than the sum of its proper divisors (10501649).

81705151 is a wasteful number, since it uses less digits than its factorization.

81705151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256169.

The product of its (nonzero) digits is 1400, while the sum is 28.

The square root of 81705151 is about 9039.0901643915. The cubic root of 81705151 is about 433.9268053137.

Adding to 81705151 its reverse (15150718), we get a palindrome (96855869).

The spelling of 81705151 in words is "eighty-one million, seven hundred five thousand, one hundred fifty-one".