81778137800 has 48 divisors (see below), whose sum is σ = 190160180160. Its totient is φ = 32706780480.

The previous prime is 81778137797. The next prime is 81778137803. The reversal of 81778137800 is 873187718.

It is an interprime number because it is at equal distance from previous prime (81778137797) and next prime (81778137803).

It is a Harshad number since it is a multiple of its sum of digits (50).

It is not an unprimeable number, because it can be changed into a prime (81778137803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1705757 + ... + 1753043.

It is an arithmetic number, because the mean of its divisors is an integer number (3961670420).

Almost surely, 2^81778137800 is an apocalyptic number.

It is an amenable number.

81778137800 is an abundant number, since it is smaller than the sum of its proper divisors (108382042360).

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

81778137800 is a wasteful number, since it uses less digits than its factorization.

81778137800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55950 (or 55941 counting only the distinct ones).

The product of its (nonzero) digits is 526848, while the sum is 50.

The spelling of 81778137800 in words is "eighty-one billion, seven hundred seventy-eight million, one hundred thirty-seven thousand, eight hundred".