220531661 has 16 divisors (see below), whose sum is σ = 263692800. Its totient is φ = 180481920.

The previous prime is 220531657. The next prime is 220531691. The reversal of 220531661 is 166135022.

220531661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 220531661 - 2² = 220531657 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 220531661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220531691) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5315 + ... + 21663.

It is an arithmetic number, because the mean of its divisors is an integer number (16480800).

Almost surely, 2^220531661 is an apocalyptic number.

It is an amenable number.

220531661 is a deficient number, since it is larger than the sum of its proper divisors (43161139).

220531661 is a wasteful number, since it uses less digits than its factorization.

220531661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16444.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 220531661 is about 14850.3084479751. The cubic root of 220531661 is about 604.1669759322.

Adding to 220531661 its reverse (166135022), we get a palindrome (386666683).

The spelling of 220531661 in words is "two hundred twenty million, five hundred thirty-one thousand, six hundred sixty-one".