64642442220621 has 12 divisors (see below), whose sum is σ = 98864911631772. Its totient is φ = 40559963746176.

The previous prime is 64642442220617. The next prime is 64642442220647. The reversal of 64642442220621 is 12602224424646.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 31957381323396 + 32685060897225 = 5653086^2 + 5717085^2 .

It is not a de Polignac number, because 64642442220621 - 2² = 64642442220617 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64642442222621) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 211249811026 + ... + 211249811331.

It is an arithmetic number, because the mean of its divisors is an integer number (8238742635981).

Almost surely, 2^{64642442220621} is an apocalyptic number.

It is an amenable number.

64642442220621 is a deficient number, since it is larger than the sum of its proper divisors (34222469411151).

64642442220621 is a wasteful number, since it uses less digits than its factorization.

64642442220621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422499622380 (or 422499622377 counting only the distinct ones).

The product of its (nonzero) digits is 1769472, while the sum is 45.

The spelling of 64642442220621 in words is "sixty-four trillion, six hundred forty-two billion, four hundred forty-two million, two hundred twenty thousand, six hundred twenty-one".