6421553 has 4 divisors (see below), whose sum is σ = 6444528. Its totient is φ = 6398580.

The previous prime is 6421523. The next prime is 6421559. The reversal of 6421553 is 3551246.

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 6421553 - 2¹² = 6417457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6421559) 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, 11063 + ... + 11628.

It is an arithmetic number, because the mean of its divisors is an integer number (1611132).

Almost surely, 2^6421553 is an apocalyptic number.

It is an amenable number.

6421553 is a deficient number, since it is larger than the sum of its proper divisors (22975).

6421553 is a wasteful number, since it uses less digits than its factorization.

6421553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22974.

The product of its digits is 3600, while the sum is 26.

The square root of 6421553 is about 2534.0783334380. The cubic root of 6421553 is about 185.8717368309.

Adding to 6421553 its reverse (3551246), we get a palindrome (9972799).

The spelling of 6421553 in words is "six million, four hundred twenty-one thousand, five hundred fifty-three".