81427973 has 8 divisors (see below), whose sum is σ = 88903200. Its totient is φ = 73964880.

The previous prime is 81427967. The next prime is 81427987. The reversal of 81427973 is 37972418.

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

It is not a de Polignac number, because 81427973 - 2¹⁸ = 81165829 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81427973.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81423973) 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, 16511 + ... + 20867.

It is an arithmetic number, because the mean of its divisors is an integer number (11112900).

Almost surely, 2^81427973 is an apocalyptic number.

It is an amenable number.

81427973 is a deficient number, since it is larger than the sum of its proper divisors (7475227).

81427973 is a wasteful number, since it uses less digits than its factorization.

81427973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6067.

The product of its digits is 84672, while the sum is 41.

The square root of 81427973 is about 9023.7449542859. The cubic root of 81427973 is about 433.4355624029.

The spelling of 81427973 in words is "eighty-one million, four hundred twenty-seven thousand, nine hundred seventy-three".