6521651421 has 4 divisors (see below), whose sum is σ = 8695535232. Its totient is φ = 4347767612.

The previous prime is 6521651419. The next prime is 6521651441. The reversal of 6521651421 is 1241561256.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6521651421 - 2¹ = 6521651419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6521651441) 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, 1086941901 + ... + 1086941906.

It is an arithmetic number, because the mean of its divisors is an integer number (2173883808).

Almost surely, 2^6521651421 is an apocalyptic number.

It is an amenable number.

6521651421 is a deficient number, since it is larger than the sum of its proper divisors (2173883811).

6521651421 is a wasteful number, since it uses less digits than its factorization.

6521651421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2173883810.

The product of its digits is 14400, while the sum is 33.

The square root of 6521651421 is about 80756.7422634172. The cubic root of 6521651421 is about 1868.3254400954.

The spelling of 6521651421 in words is "six billion, five hundred twenty-one million, six hundred fifty-one thousand, four hundred twenty-one".