6551521 has 4 divisors (see below), whose sum is σ = 6615232. Its totient is φ = 6487812.

The previous prime is 6551497. The next prime is 6551533. The reversal of 6551521 is 1251556.

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 6551521 - 2⁷ = 6551393 is a prime.

It is a Duffinian number.

6551521 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6551581) 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, 31701 + ... + 31906.

It is an arithmetic number, because the mean of its divisors is an integer number (1653808).

Almost surely, 2^6551521 is an apocalyptic number.

It is an amenable number.

6551521 is a deficient number, since it is larger than the sum of its proper divisors (63711).

6551521 is a wasteful number, since it uses less digits than its factorization.

6551521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63710.

The product of its digits is 1500, while the sum is 25.

The square root of 6551521 is about 2559.5939131042. The cubic root of 6551521 is about 187.1173446343.

It can be divided in two parts, 65515 and 21, that added together give a 16-th power (65536 = 2¹⁶).

The spelling of 6551521 in words is "six million, five hundred fifty-one thousand, five hundred twenty-one".