81081770 has 80 divisors (see below), whose sum is σ = 186344928. Its totient is φ = 25189920.

The previous prime is 81081769. The next prime is 81081773. The reversal of 81081770 is 7718018.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81081773) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 263957 + ... + 264263.

Almost surely, 2^81081770 is an apocalyptic number.

81081770 is an abundant number, since it is smaller than the sum of its proper divisors (105263158).

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

81081770 is a wasteful number, since it uses less digits than its factorization.

81081770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 353 (or 332 counting only the distinct ones).

The product of its (nonzero) digits is 3136, while the sum is 32.

The square root of 81081770 is about 9004.5416318656. The cubic root of 81081770 is about 432.8204181107.

Adding to 81081770 its reverse (7718018), we get a palindrome (88799788).

The spelling of 81081770 in words is "eighty-one million, eighty-one thousand, seven hundred seventy".