817978032144 has 1600 divisors, whose sum is σ = 3294014169600. Its totient is φ = 189621927936.

The previous prime is 817978032139. The next prime is 817978032173. The reversal of 817978032144 is 441230879718.

It is a super-2 number, since 2×817978032144² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 4152172654 + ... + 4152172850.

It is an arithmetic number, because the mean of its divisors is an integer number (2058758856).

Almost surely, 2^817978032144 is an apocalyptic number.

817978032144 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 817978032144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1647007084800).

817978032144 is an abundant number, since it is smaller than the sum of its proper divisors (2476036137456).

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

817978032144 is a wasteful number, since it uses less digits than its factorization.

817978032144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 367 counting only the distinct ones).

The product of its (nonzero) digits is 2709504, while the sum is 54.

The spelling of 817978032144 in words is "eight hundred seventeen billion, nine hundred seventy-eight million, thirty-two thousand, one hundred forty-four".