6565921421 has 16 divisors (see below), whose sum is σ = 6832573440. Its totient is φ = 6305206320.

The previous prime is 6565921393. The next prime is 6565921433. The reversal of 6565921421 is 1241295656.

It is a cyclic number.

It is not a de Polignac number, because 6565921421 - 2¹⁴ = 6565905037 is a prime.

It is a super-2 number, since 2×6565921421² = 86222648213493318482, which contains 22 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 (6565921471) 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, 748700 + ... + 757418.

It is an arithmetic number, because the mean of its divisors is an integer number (427035840).

Almost surely, 2^6565921421 is an apocalyptic number.

It is an amenable number.

6565921421 is a deficient number, since it is larger than the sum of its proper divisors (266652019).

6565921421 is a wasteful number, since it uses less digits than its factorization.

6565921421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9056.

The product of its digits is 129600, while the sum is 41.

The square root of 6565921421 is about 81030.3734472451. The cubic root of 6565921421 is about 1872.5434064387.

The spelling of 6565921421 in words is "six billion, five hundred sixty-five million, nine hundred twenty-one thousand, four hundred twenty-one".