81919425000 has 288 divisors, whose sum is σ = 297788127840. Its totient is φ = 18723600000.

The previous prime is 81919424987. The next prime is 81919425017. The reversal of 81919425000 is 52491918.

It is a self number, because there is not a number n which added to its sum of digits gives 81919425000.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 3663855 + ... + 3686145.

It is an arithmetic number, because the mean of its divisors is an integer number (1033986555).

Almost surely, 2^81919425000 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 81919425000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (148894063920).

81919425000 is an abundant number, since it is smaller than the sum of its proper divisors (215868702840).

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

81919425000 is a wasteful number, since it uses less digits than its factorization.

81919425000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22339 (or 22308 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 39.

The spelling of 81919425000 in words is "eighty-one billion, nine hundred nineteen million, four hundred twenty-five thousand".