81427727 has 4 divisors (see below), whose sum is σ = 81446736. Its totient is φ = 81408720.

The previous prime is 81427721. The next prime is 81427747. The reversal of 81427727 is 72772418.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 72772418 = 2 ⋅36386209.

It is a cyclic number.

It is not a de Polignac number, because 81427727 - 2¹² = 81423631 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 (81427721) 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, 278 + ... + 12764.

It is an arithmetic number, because the mean of its divisors is an integer number (20361684).

Almost surely, 2^81427727 is an apocalyptic number.

81427727 is a deficient number, since it is larger than the sum of its proper divisors (19009).

81427727 is a wasteful number, since it uses less digits than its factorization.

81427727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19008.

The product of its digits is 43904, while the sum is 38.

The square root of 81427727 is about 9023.7313235712. The cubic root of 81427727 is about 433.4351259221.

The spelling of 81427727 in words is "eighty-one million, four hundred twenty-seven thousand, seven hundred twenty-seven".