81788266 has 32 divisors (see below), whose sum is σ = 142813440. Its totient is φ = 34407936.

The previous prime is 81788263. The next prime is 81788269. The reversal of 81788266 is 66288718.

It is an interprime number because it is at equal distance from previous prime (81788263) and next prime (81788269).

It is not an unprimeable number, because it can be changed into a prime (81788263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 310851 + ... + 311113.

It is an arithmetic number, because the mean of its divisors is an integer number (4462920).

Almost surely, 2^81788266 is an apocalyptic number.

81788266 is a deficient number, since it is larger than the sum of its proper divisors (61025174).

81788266 is a wasteful number, since it uses less digits than its factorization.

81788266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 598.

The product of its digits is 258048, while the sum is 46.

The square root of 81788266 is about 9043.6865270751. The cubic root of 81788266 is about 434.0738935674.

The spelling of 81788266 in words is "eighty-one million, seven hundred eighty-eight thousand, two hundred sixty-six".