81329351 has 4 divisors (see below), whose sum is σ = 81393072. Its totient is φ = 81265632.

The previous prime is 81329327. The next prime is 81329371. The reversal of 81329351 is 15392318.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81329351 - 2¹⁴ = 81312967 is a prime.

It is a super-2 number, since 2×81329351² = 13228926668162402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81329371) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29906 + ... + 32511.

It is an arithmetic number, because the mean of its divisors is an integer number (20348268).

Almost surely, 2^81329351 is an apocalyptic number.

81329351 is a deficient number, since it is larger than the sum of its proper divisors (63721).

81329351 is a wasteful number, since it uses less digits than its factorization.

81329351 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63720.

The product of its digits is 6480, while the sum is 32.

The square root of 81329351 is about 9018.2787160300. The cubic root of 81329351 is about 433.2605056440.

The spelling of 81329351 in words is "eighty-one million, three hundred twenty-nine thousand, three hundred fifty-one".