6215661 has 6 divisors (see below), whose sum is σ = 8978190. Its totient is φ = 4143768.

The previous prime is 6215653. The next prime is 6215669. The reversal of 6215661 is 1665126.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (6215653) and next prime (6215669).

It can be written as a sum of positive squares in only one way, i.e., 3493161 + 2722500 = 1869^2 + 1650^2 .

It is not a de Polignac number, because 6215661 - 2³ = 6215653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6215669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 345306 + ... + 345323.

It is an arithmetic number, because the mean of its divisors is an integer number (1496365).

Almost surely, 2^6215661 is an apocalyptic number.

It is an amenable number.

6215661 is a deficient number, since it is larger than the sum of its proper divisors (2762529).

6215661 is a wasteful number, since it uses less digits than its factorization.

6215661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 690635 (or 690632 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 6215661 is about 2493.1227406608. The cubic root of 6215661 is about 183.8636059930.

The spelling of 6215661 in words is "six million, two hundred fifteen thousand, six hundred sixty-one".