81637673 has 8 divisors (see below), whose sum is σ = 88017216. Its totient is φ = 75272400.

The previous prime is 81637669. The next prime is 81637681. The reversal of 81637673 is 37673618.

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

It is a cyclic number.

It is not a de Polignac number, because 81637673 - 2² = 81637669 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 81637673.

It is not an unprimeable number, because it can be changed into a prime (81634673) 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, 10358 + ... + 16448.

It is an arithmetic number, because the mean of its divisors is an integer number (11002152).

Almost surely, 2^81637673 is an apocalyptic number.

It is an amenable number.

81637673 is a deficient number, since it is larger than the sum of its proper divisors (6379543).

81637673 is a wasteful number, since it uses less digits than its factorization.

81637673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7135.

The product of its digits is 127008, while the sum is 41.

The square root of 81637673 is about 9035.3568274861. The cubic root of 81637673 is about 433.8073164077.

The spelling of 81637673 in words is "eighty-one million, six hundred thirty-seven thousand, six hundred seventy-three".