81563814 has 24 divisors (see below), whose sum is σ = 181400520. Its totient is φ = 27165816.

The previous prime is 81563813. The next prime is 81563837. The reversal of 81563814 is 41836518.

81563814 is a `hidden beast` number, since 8 + 1 + 5 + 638 + 14 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81563813) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 65752 + ... + 66980.

It is an arithmetic number, because the mean of its divisors is an integer number (7558355).

Almost surely, 2^81563814 is an apocalyptic number.

81563814 is an abundant number, since it is smaller than the sum of its proper divisors (99836706).

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

81563814 is an equidigital number, since it uses as much as digits as its factorization.

81563814 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2469 (or 1234 counting only the distinct ones).

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

The square root of 81563814 is about 9031.2686816416. The cubic root of 81563814 is about 433.6764526336.

The spelling of 81563814 in words is "eighty-one million, five hundred sixty-three thousand, eight hundred fourteen".