21517325427666 has 16 divisors (see below), whose sum is σ = 43041353105088. Its totient is φ = 7171324767600.

The previous prime is 21517325427659. The next prime is 21517325427667. The reversal of 21517325427666 is 66672452371512.

It is not an unprimeable number, because it can be changed into a prime (21517325427667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 279218670 + ... + 279295721.

It is an arithmetic number, because the mean of its divisors is an integer number (2690084569068).

Almost surely, 2^{21517325427666} is an apocalyptic number.

21517325427666 is an abundant number, since it is smaller than the sum of its proper divisors (21524027677422).

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

21517325427666 is a wasteful number, since it uses less digits than its factorization.

21517325427666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 558520817.

The product of its digits is 25401600, while the sum is 57.

The spelling of 21517325427666 in words is "twenty-one trillion, five hundred seventeen billion, three hundred twenty-five million, four hundred twenty-seven thousand, six hundred sixty-six".