61644281 has 4 divisors (see below), whose sum is σ = 61913700. Its totient is φ = 61374864.

The previous prime is 61644269. The next prime is 61644287. The reversal of 61644281 is 18244616.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 25452025 + 36192256 = 5045^2 + 6016^2 .

It is a cyclic number.

It is not a de Polignac number, because 61644281 - 2⁶ = 61644217 is a prime.

It is a super-2 number, since 2×61644281² = 7600034760013922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61644287) 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 3 ways as a sum of consecutive naturals, for example, 134366 + ... + 134823.

It is an arithmetic number, because the mean of its divisors is an integer number (15478425).

Almost surely, 2^61644281 is an apocalyptic number.

It is an amenable number.

61644281 is a deficient number, since it is larger than the sum of its proper divisors (269419).

61644281 is a wasteful number, since it uses less digits than its factorization.

61644281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269418.

The product of its digits is 9216, while the sum is 32.

The square root of 61644281 is about 7851.3872022720. The cubic root of 61644281 is about 395.0307747213.

Adding to 61644281 its reverse (18244616), we get a palindrome (79888897).

The spelling of 61644281 in words is "sixty-one million, six hundred forty-four thousand, two hundred eighty-one".