665171742690 has 1024 divisors, whose sum is σ = 2439110983680. Its totient is φ = 124993290240.

The previous prime is 665171742649. The next prime is 665171742727. The reversal of 665171742690 is 96247171566.

665171742690 is a `hidden beast` number, since 6 + 6 + 517 + 17 + 4 + 26 + 90 = 666.

It is a super-2 number, since 2×665171742690² (a number of 24 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 511 ways as a sum of consecutive naturals, for example, 608573784 + ... + 608574876.

It is an arithmetic number, because the mean of its divisors is an integer number (2381944320).

Almost surely, 2^665171742690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665171742690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1219555491840).

665171742690 is an abundant number, since it is smaller than the sum of its proper divisors (1773939240990).

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

665171742690 is a wasteful number, since it uses less digits than its factorization.

665171742690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1224 (or 1218 counting only the distinct ones).

The product of its (nonzero) digits is 3810240, while the sum is 54.

The spelling of 665171742690 in words is "six hundred sixty-five billion, one hundred seventy-one million, seven hundred forty-two thousand, six hundred ninety".