521742266013666 has 16 divisors (see below), whose sum is σ = 1043484761539584. Its totient is φ = 173914050419184.

The previous prime is 521742266013623. The next prime is 521742266013677. The reversal of 521742266013666 is 666310662247125.

It is a happy number.

It is a super-2 number, since 2×521742266013666² (a number of 30 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38816991 + ... + 50499933.

It is an arithmetic number, because the mean of its divisors is an integer number (65217797596224).

Almost surely, 2^{521742266013666} is an apocalyptic number.

521742266013666 is an abundant number, since it is smaller than the sum of its proper divisors (521742495525918).

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

521742266013666 is a wasteful number, since it uses less digits than its factorization.

521742266013666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19126025.

The product of its (nonzero) digits is 26127360, while the sum is 57.

The spelling of 521742266013666 in words is "five hundred twenty-one trillion, seven hundred forty-two billion, two hundred sixty-six million, thirteen thousand, six hundred sixty-six".