81337506 has 8 divisors (see below), whose sum is σ = 162675024. Its totient is φ = 27112500.

The previous prime is 81337411. The next prime is 81337511. The reversal of 81337506 is 60573318.

It is a happy number.

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

81337506 is an admirable number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6778120 + ... + 6778131.

It is an arithmetic number, because the mean of its divisors is an integer number (20334378).

Almost surely, 2^81337506 is an apocalyptic number.

81337506 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81337506 is a wasteful number, since it uses less digits than its factorization.

81337506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13556256.

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 81337506 is about 9018.7308419755. The cubic root of 81337506 is about 433.2749863584.

The spelling of 81337506 in words is "eighty-one million, three hundred thirty-seven thousand, five hundred six".