64640662042221 has 24 divisors (see below), whose sum is σ = 93669753172320. Its totient is φ = 42955405178400.

The previous prime is 64640662042211. The next prime is 64640662042241. The reversal of 64640662042221 is 12224026604646.

It is not a de Polignac number, because 64640662042221 - 2⁵ = 64640662042189 is a prime.

It is a super-2 number, since 2×64640662042221² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64640662042211) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13610290 + ... + 17734748.

It is an arithmetic number, because the mean of its divisors is an integer number (3902906382180).

Almost surely, 2^{64640662042221} is an apocalyptic number.

It is an amenable number.

64640662042221 is a deficient number, since it is larger than the sum of its proper divisors (29029091130099).

64640662042221 is a wasteful number, since it uses less digits than its factorization.

64640662042221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4130057 (or 4130054 counting only the distinct ones).

The product of its (nonzero) digits is 1327104, while the sum is 45.

Adding to 64640662042221 its reverse (12224026604646), we get a palindrome (76864688646867).

The spelling of 64640662042221 in words is "sixty-four trillion, six hundred forty billion, six hundred sixty-two million, forty-two thousand, two hundred twenty-one".