817779261027456 has 3072 divisors, whose sum is σ = 3216755662848000. Its totient is φ = 194653111910400.

The previous prime is 817779261027431. The next prime is 817779261027461. The reversal of 817779261027456 is 654720162977718.

It is a happy number.

817779261027456 is a `hidden beast` number, since 8 + 1 + 7 + 7 + 7 + 92 + 61 + 0 + 27 + 456 = 666.

It is a super-2 number, since 2×817779261027456² (a number of 31 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 517909600875 + ... + 517909602453.

It is an arithmetic number, because the mean of its divisors is an integer number (1047120984000).

Almost surely, 2^{817779261027456} 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 817779261027456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1608377831424000).

817779261027456 is an abundant number, since it is smaller than the sum of its proper divisors (2398976401820544).

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

817779261027456 is a wasteful number, since it uses less digits than its factorization.

817779261027456 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1740 (or 1699 counting only the distinct ones).

The product of its (nonzero) digits is 497871360, while the sum is 72.

The spelling of 817779261027456 in words is "eight hundred seventeen trillion, seven hundred seventy-nine billion, two hundred sixty-one million, twenty-seven thousand, four hundred fifty-six".