81219078 has 16 divisors (see below), whose sum is σ = 180486960. Its totient is φ = 27073008.

The previous prime is 81219071. The next prime is 81219079. The reversal of 81219078 is 87091218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81219071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 751975 + ... + 752082.

It is an arithmetic number, because the mean of its divisors is an integer number (11280435).

Almost surely, 2^81219078 is an apocalyptic number.

81219078 is an abundant number, since it is smaller than the sum of its proper divisors (99267882).

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

81219078 is a wasteful number, since it uses less digits than its factorization.

81219078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1504068 (or 1504062 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 81219078 is about 9012.1627814859. The cubic root of 81219078 is about 433.0646003743.

The spelling of 81219078 in words is "eighty-one million, two hundred nineteen thousand, seventy-eight".