81357668 has 12 divisors (see below), whose sum is σ = 162715392. Its totient is φ = 34867560.

The previous prime is 81357623. The next prime is 81357781. The reversal of 81357668 is 86675318.

81357668 is an admirable number.

It is a super-3 number, since 3×81357668³ (a number of 25 digits) contains 333 as substring.

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, 1452788 + ... + 1452843.

It is an arithmetic number, because the mean of its divisors is an integer number (13559616).

Almost surely, 2^81357668 is an apocalyptic number.

It is an amenable number.

81357668 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.

81357668 is a wasteful number, since it uses less digits than its factorization.

81357668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2905642 (or 2905640 counting only the distinct ones).

The product of its digits is 241920, while the sum is 44.

The square root of 81357668 is about 9019.8485574870. The cubic root of 81357668 is about 433.3107835735.

The spelling of 81357668 in words is "eighty-one million, three hundred fifty-seven thousand, six hundred sixty-eight".