21125106346566 has 16 divisors (see below), whose sum is σ = 42342663929904. Its totient is φ = 7026293576064.

The previous prime is 21125106346543. The next prime is 21125106346583. The reversal of 21125106346566 is 66564360152112.

It is a happy number.

It is a congruent number.

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, 3852131895 + ... + 3852137378.

It is an arithmetic number, because the mean of its divisors is an integer number (2646416495619).

Almost surely, 2^{21125106346566} is an apocalyptic number.

21125106346566 is an abundant number, since it is smaller than the sum of its proper divisors (21217557583338).

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

21125106346566 is a wasteful number, since it uses less digits than its factorization.

21125106346566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7704269735.

The product of its (nonzero) digits is 1555200, while the sum is 48.

Adding to 21125106346566 its reverse (66564360152112), we get a palindrome (87689466498678).

The spelling of 21125106346566 in words is "twenty-one trillion, one hundred twenty-five billion, one hundred six million, three hundred forty-six thousand, five hundred sixty-six".