81688270 has 16 divisors (see below), whose sum is σ = 148468320. Its totient is φ = 32357664.

The previous prime is 81688253. The next prime is 81688297. The reversal of 81688270 is 7288618.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38625 + ... + 40684.

It is an arithmetic number, because the mean of its divisors is an integer number (9279270).

Almost surely, 2^81688270 is an apocalyptic number.

81688270 is a deficient number, since it is larger than the sum of its proper divisors (66780050).

81688270 is a wasteful number, since it uses less digits than its factorization.

81688270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79419.

The product of its (nonzero) digits is 43008, while the sum is 40.

The square root of 81688270 is about 9038.1563385460. The cubic root of 81688270 is about 433.8969188955.

The spelling of 81688270 in words is "eighty-one million, six hundred eighty-eight thousand, two hundred seventy".