943521661 has 4 divisors (see below), whose sum is σ = 943895232. Its totient is φ = 943148092.

The previous prime is 943521647. The next prime is 943521679. The reversal of 943521661 is 166125349.

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, and also an emirpimes, since its reverse is a distinct semiprime: 166125349 = 13 ⋅12778873.

It is a cyclic number.

It is not a de Polignac number, because 943521661 - 2⁵ = 943521629 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 943521661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (943521461) 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, 182971 + ... + 188056.

It is an arithmetic number, because the mean of its divisors is an integer number (235973808).

Almost surely, 2^943521661 is an apocalyptic number.

It is an amenable number.

943521661 is a deficient number, since it is larger than the sum of its proper divisors (373571).

943521661 is a wasteful number, since it uses less digits than its factorization.

943521661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 373570.

The product of its digits is 38880, while the sum is 37.

The square root of 943521661 is about 30716.7977009323. The cubic root of 943521661 is about 980.8079069466.

The spelling of 943521661 in words is "nine hundred forty-three million, five hundred twenty-one thousand, six hundred sixty-one".