81934159 has 4 divisors (see below), whose sum is σ = 82113904. Its totient is φ = 81754416.

The previous prime is 81934157. The next prime is 81934183. The reversal of 81934159 is 95143918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 95143918 = 2 ⋅47571959.

It is a cyclic number.

It is not a de Polignac number, because 81934159 - 2¹ = 81934157 is a prime.

It is a super-2 number, since 2×81934159² = 13426412822074562, 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 (81934157) 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, 89187 + ... + 90100.

It is an arithmetic number, because the mean of its divisors is an integer number (20528476).

Almost surely, 2^81934159 is an apocalyptic number.

81934159 is a deficient number, since it is larger than the sum of its proper divisors (179745).

81934159 is a wasteful number, since it uses less digits than its factorization.

81934159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179744.

The product of its digits is 38880, while the sum is 40.

The square root of 81934159 is about 9051.7489470268. The cubic root of 81934159 is about 434.3318389839.

The spelling of 81934159 in words is "eighty-one million, nine hundred thirty-four thousand, one hundred fifty-nine".