21055565607064 has 8 divisors (see below), whose sum is σ = 39479185513260. Its totient is φ = 10527782803528.

The previous prime is 21055565607061. The next prime is 21055565607071. The reversal of 21055565607064 is 46070656555012.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055565607061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1315972850434 + ... + 1315972850449.

Almost surely, 2^{21055565607064} is an apocalyptic number.

It is an amenable number.

21055565607064 is a deficient number, since it is larger than the sum of its proper divisors (18423619906196).

21055565607064 is a wasteful number, since it uses less digits than its factorization.

21055565607064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631945700889 (or 2631945700885 counting only the distinct ones).

The product of its (nonzero) digits is 7560000, while the sum is 52.

The spelling of 21055565607064 in words is "twenty-one trillion, fifty-five billion, five hundred sixty-five million, six hundred seven thousand, sixty-four".