81688410 has 192 divisors, whose sum is σ = 244408320. Its totient is φ = 18817920.

The previous prime is 81688393. The next prime is 81688427. The reversal of 81688410 is 1488618.

It is an interprime number because it is at equal distance from previous prime (81688393) and next prime (81688427).

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 95 ways as a sum of consecutive naturals, for example, 1219197 + ... + 1219263.

It is an arithmetic number, because the mean of its divisors is an integer number (1272960).

Almost surely, 2^81688410 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81688410, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122204160).

81688410 is an abundant number, since it is smaller than the sum of its proper divisors (162719910).

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

81688410 is a wasteful number, since it uses less digits than its factorization.

81688410 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 36.

The square root of 81688410 is about 9038.1640834851. The cubic root of 81688410 is about 433.8971667708.

The spelling of 81688410 in words is "eighty-one million, six hundred eighty-eight thousand, four hundred ten".