6621001 has 4 divisors (see below), whose sum is σ = 6729604. Its totient is φ = 6512400.

The previous prime is 6620981. The next prime is 6621029. The reversal of 6621001 is 1001266.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2822400 + 3798601 = 1680^2 + 1949^2 .

It is a cyclic number.

It is not a de Polignac number, because 6621001 - 2⁹ = 6620489 is a prime.

It is a Duffinian number.

6621001 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6621061) 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, 54210 + ... + 54331.

It is an arithmetic number, because the mean of its divisors is an integer number (1682401).

Almost surely, 2^6621001 is an apocalyptic number.

6621001 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

6621001 is a deficient number, since it is larger than the sum of its proper divisors (108603).

6621001 is a wasteful number, since it uses less digits than its factorization.

6621001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108602.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 6621001 is about 2573.1305835499. The cubic root of 6621001 is about 187.7764904528.

Adding to 6621001 its reverse (1001266), we get a palindrome (7622267).

The spelling of 6621001 in words is "six million, six hundred twenty-one thousand, one".