61217221 has 32 divisors (see below), whose sum is σ = 74995200. Its totient is φ = 49351680.

The previous prime is 61217213. The next prime is 61217227. The reversal of 61217221 is 12271216.

It is a happy number.

61217221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 61217221 - 2³ = 61217213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61217192 and 61217201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61217227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 256020 + ... + 256258.

It is an arithmetic number, because the mean of its divisors is an integer number (2343600).

Almost surely, 2^61217221 is an apocalyptic number.

61217221 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

It is an amenable number.

61217221 is a deficient number, since it is larger than the sum of its proper divisors (13777979).

61217221 is a wasteful number, since it uses less digits than its factorization.

61217221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 349.

The product of its digits is 336, while the sum is 22.

The square root of 61217221 is about 7824.1434674985. The cubic root of 61217221 is about 394.1164269803.

Adding to 61217221 its reverse (12271216), we get a palindrome (73488437).

The spelling of 61217221 in words is "sixty-one million, two hundred seventeen thousand, two hundred twenty-one".