81863145 has 48 divisors (see below), whose sum is σ = 174650112. Its totient is φ = 34542720.

The previous prime is 81863113. The next prime is 81863161. The reversal of 81863145 is 54136818.

81863145 is a `hidden beast` number, since 8 + 18 + 631 + 4 + 5 = 666.

It is not a de Polignac number, because 81863145 - 2⁵ = 81863113 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5901 + ... + 14090.

It is an arithmetic number, because the mean of its divisors is an integer number (3638544).

Almost surely, 2^81863145 is an apocalyptic number.

It is an amenable number.

81863145 is an abundant number, since it is smaller than the sum of its proper divisors (92786967).

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

81863145 is a wasteful number, since it uses less digits than its factorization.

81863145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20022 (or 20019 counting only the distinct ones).

The product of its digits is 23040, while the sum is 36.

The square root of 81863145 is about 9047.8254293504. The cubic root of 81863145 is about 434.2063213048.

The spelling of 81863145 in words is "eighty-one million, eight hundred sixty-three thousand, one hundred forty-five".