6516642660421 has 16 divisors (see below), whose sum is σ = 6575702031360. Its totient is φ = 6457860581760.

The previous prime is 6516642660397. The next prime is 6516642660427. The reversal of 6516642660421 is 1240662466156.

It is a cyclic number.

It is not a de Polignac number, because 6516642660421 - 2¹¹ = 6516642658373 is a prime.

It is a super-3 number, since 3×6516642660421³ (a number of 39 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6516642660427) 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, 391828776 + ... + 391845406.

It is an arithmetic number, because the mean of its divisors is an integer number (410981376960).

Almost surely, 2^{6516642660421} is an apocalyptic number.

It is an amenable number.

6516642660421 is a deficient number, since it is larger than the sum of its proper divisors (59059370939).

6516642660421 is a wasteful number, since it uses less digits than its factorization.

6516642660421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24756.

The product of its (nonzero) digits is 2488320, while the sum is 49.

The spelling of 6516642660421 in words is "six trillion, five hundred sixteen billion, six hundred forty-two million, six hundred sixty thousand, four hundred twenty-one".