81278000 has 40 divisors (see below), whose sum is σ = 196535040. Its totient is φ = 32510400.

The previous prime is 81277979. The next prime is 81278009. The reversal of 81278000 is 87218.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×81278000² = 13212226568000000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81278009) 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, 18320 + ... + 22319.

It is an arithmetic number, because the mean of its divisors is an integer number (4913376).

Almost surely, 2^81278000 is an apocalyptic number.

81278000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81278000 is an abundant number, since it is smaller than the sum of its proper divisors (115257040).

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

81278000 is a wasteful number, since it uses less digits than its factorization.

81278000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40662 (or 40646 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 26.

The square root of 81278000 is about 9015.4312154217. The cubic root of 81278000 is about 433.1693001767.

The spelling of 81278000 in words is "eighty-one million, two hundred seventy-eight thousand".