61644221 has 8 divisors (see below), whose sum is σ = 63594144. Its totient is φ = 59724720.

The previous prime is 61644217. The next prime is 61644223. The reversal of 61644221 is 12244616.

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 61644221 - 2² = 61644217 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 (61644223) 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 7 ways as a sum of consecutive naturals, for example, 3455 + ... + 11628.

It is an arithmetic number, because the mean of its divisors is an integer number (7949268).

Almost surely, 2^61644221 is an apocalyptic number.

61644221 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

61644221 is a deficient number, since it is larger than the sum of its proper divisors (1949923).

61644221 is a wasteful number, since it uses less digits than its factorization.

61644221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15211.

The product of its digits is 2304, while the sum is 26.

The square root of 61644221 is about 7851.3833812902. The cubic root of 61644221 is about 395.0306465567.

Adding to 61644221 its reverse (12244616), we get a palindrome (73888837).

The spelling of 61644221 in words is "sixty-one million, six hundred forty-four thousand, two hundred twenty-one".