81378081 has 8 divisors (see below), whose sum is σ = 120560160. Its totient is φ = 54252036.

The previous prime is 81378079. The next prime is 81378091. The reversal of 81378081 is 18087318.

It is not a de Polignac number, because 81378081 - 2¹ = 81378079 is a prime.

It is a super-2 number, since 2×81378081² = 13244784134485122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81378091) 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, 1506975 + ... + 1507028.

It is an arithmetic number, because the mean of its divisors is an integer number (15070020).

Almost surely, 2^81378081 is an apocalyptic number.

It is an amenable number.

81378081 is a deficient number, since it is larger than the sum of its proper divisors (39182079).

81378081 is a wasteful number, since it uses less digits than its factorization.

81378081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3014012 (or 3014006 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 81378081 is about 9020.9800465360. The cubic root of 81378081 is about 433.3470204092.

The spelling of 81378081 in words is "eighty-one million, three hundred seventy-eight thousand, eighty-one".