812319021900 has 180 divisors, whose sum is σ = 2634345484848. Its totient is φ = 216525605760.

The previous prime is 812319021881. The next prime is 812319021901. The reversal of 812319021900 is 9120913218.

It is a tau number, because it is divible by the number of its divisors (180).

It is a super-2 number, since 2×812319021900² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (812319021901) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 20043457 + ... + 20083943.

Almost surely, 2^812319021900 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 812319021900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1317172742424).

812319021900 is an abundant number, since it is smaller than the sum of its proper divisors (1822026462948).

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

812319021900 is a wasteful number, since it uses less digits than its factorization.

812319021900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42990 (or 42974 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The spelling of 812319021900 in words is "eight hundred twelve billion, three hundred nineteen million, twenty-one thousand, nine hundred".