81051816 has 32 divisors (see below), whose sum is σ = 211440960. Its totient is φ = 25842432.

The previous prime is 81051811. The next prime is 81051821. The reversal of 81051816 is 61815018.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81051811) and next prime (81051821).

It is not an unprimeable number, because it can be changed into a prime (81051811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 72865 + ... + 73968.

It is an arithmetic number, because the mean of its divisors is an integer number (6607530).

Almost surely, 2^81051816 is an apocalyptic number.

It is an amenable number.

81051816 is an abundant number, since it is smaller than the sum of its proper divisors (130389144).

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

81051816 is a wasteful number, since it uses less digits than its factorization.

81051816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146865 (or 146861 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 30.

The square root of 81051816 is about 9002.8782064404. The cubic root of 81051816 is about 432.7671126651.

The spelling of 81051816 in words is "eighty-one million, fifty-one thousand, eight hundred sixteen".