4221556661 has 8 divisors (see below), whose sum is σ = 4871478144. Its totient is φ = 3583345680.

The previous prime is 4221556649. The next prime is 4221556673. The reversal of 4221556661 is 1666551224.

4221556661 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (4221556649) and next prime (4221556673).

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

It is a cyclic number.

It is not a de Polignac number, because 4221556661 - 2²⁶ = 4154447797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (4221556621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2926850 + ... + 2928291.

It is an arithmetic number, because the mean of its divisors is an integer number (608934768).

Almost surely, 2^4221556661 is an apocalyptic number.

It is an amenable number.

4221556661 is a deficient number, since it is larger than the sum of its proper divisors (649921483).

4221556661 is a wasteful number, since it uses less digits than its factorization.

4221556661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5855251.

The product of its digits is 86400, while the sum is 38.

The square root of 4221556661 is about 64973.5073780075. The cubic root of 4221556661 is about 1616.1842650724.

The spelling of 4221556661 in words is "four billion, two hundred twenty-one million, five hundred fifty-six thousand, six hundred sixty-one".