6651021 has 8 divisors (see below), whose sum is σ = 9550240. Its totient is φ = 4092912.

The previous prime is 6650993. The next prime is 6651049. The reversal of 6651021 is 1201566.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (6650993) and next prime (6651049).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 6651021 - 2¹³ = 6642829 is a prime.

It is an Ulam number.

It is a Duffinian number.

6651021 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6651091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85231 + ... + 85308.

It is an arithmetic number, because the mean of its divisors is an integer number (1193780).

Almost surely, 2^6651021 is an apocalyptic number.

It is an amenable number.

6651021 is a deficient number, since it is larger than the sum of its proper divisors (2899219).

6651021 is a wasteful number, since it uses less digits than its factorization.

6651021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170555.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 6651021 is about 2578.9573474565. The cubic root of 6651021 is about 188.0598590889.

Adding to 6651021 its reverse (1201566), we get a palindrome (7852587).

The spelling of 6651021 in words is "six million, six hundred fifty-one thousand, twenty-one".