646560440413121 has 4 divisors (see below), whose sum is σ = 696295858906452. Its totient is φ = 596825021919792.

The previous prime is 646560440413117. The next prime is 646560440413123. The reversal of 646560440413121 is 121314044065646.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 227414090865025 + 419146349548096 = 15080255^2 + 20473064^2 .

It is a cyclic number.

It is not a de Polignac number, because 646560440413121 - 2² = 646560440413117 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (646560440413123) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24867709246646 + ... + 24867709246671.

It is an arithmetic number, because the mean of its divisors is an integer number (174073964726613).

Almost surely, 2^{646560440413121} is an apocalyptic number.

It is an amenable number.

646560440413121 is a deficient number, since it is larger than the sum of its proper divisors (49735418493331).

646560440413121 is a wasteful number, since it uses less digits than its factorization.

646560440413121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49735418493330.

The product of its (nonzero) digits is 1658880, while the sum is 47.

Adding to 646560440413121 its reverse (121314044065646), we get a palindrome (767874484478767).

The spelling of 646560440413121 in words is "six hundred forty-six trillion, five hundred sixty billion, four hundred forty million, four hundred thirteen thousand, one hundred twenty-one".