71821815780 has 192 divisors, whose sum is σ = 241286750208. Its totient is φ = 15729968640.

The previous prime is 71821815739. The next prime is 71821815799. The reversal of 71821815780 is 8751812817.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 314209 + ... + 492311.

It is an arithmetic number, because the mean of its divisors is an integer number (1256701824).

Almost surely, 2^71821815780 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71821815780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120643375104).

71821815780 is an abundant number, since it is smaller than the sum of its proper divisors (169464934428).

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

71821815780 is a wasteful number, since it uses less digits than its factorization.

71821815780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178186 (or 178184 counting only the distinct ones).

The product of its (nonzero) digits is 250880, while the sum is 48.

The spelling of 71821815780 in words is "seventy-one billion, eight hundred twenty-one million, eight hundred fifteen thousand, seven hundred eighty".