81215850428 has 6 divisors (see below), whose sum is σ = 142127738256. Its totient is φ = 40607925212.

The previous prime is 81215850427. The next prime is 81215850503. The reversal of 81215850428 is 82405851218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81215850427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10151981300 + ... + 10151981307.

It is an arithmetic number, because the mean of its divisors is an integer number (23687956376).

Almost surely, 2^81215850428 is an apocalyptic number.

It is an amenable number.

81215850428 is a deficient number, since it is larger than the sum of its proper divisors (60911887828).

81215850428 is a wasteful number, since it uses less digits than its factorization.

81215850428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20303962611 (or 20303962609 counting only the distinct ones).

The product of its (nonzero) digits is 204800, while the sum is 44.

The spelling of 81215850428 in words is "eighty-one billion, two hundred fifteen million, eight hundred fifty thousand, four hundred twenty-eight".