646512216444321 has 16 divisors (see below), whose sum is σ = 899498399415936. Its totient is φ = 412267219790976.

The previous prime is 646512216444317. The next prime is 646512216444491. The reversal of 646512216444321 is 123444612215646.

It is not a de Polignac number, because 646512216444321 - 2² = 646512216444317 is a prime.

It is not an unprimeable number, because it can be changed into a prime (646512216442321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3711981 + ... + 36149733.

It is an arithmetic number, because the mean of its divisors is an integer number (56218649963496).

Almost surely, 2^{646512216444321} is an apocalyptic number.

It is an amenable number.

646512216444321 is a deficient number, since it is larger than the sum of its proper divisors (252986182971615).

646512216444321 is a wasteful number, since it uses less digits than its factorization.

646512216444321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32726632.

The product of its digits is 6635520, while the sum is 51.

Adding to 646512216444321 its reverse (123444612215646), we get a palindrome (769956828659967).

The spelling of 646512216444321 in words is "six hundred forty-six trillion, five hundred twelve billion, two hundred sixteen million, four hundred forty-four thousand, three hundred twenty-one".