61221209 has 8 divisors (see below), whose sum is σ = 70150080. Its totient is φ = 52338096.

The previous prime is 61221203. The next prime is 61221221. The reversal of 61221209 is 90212216.

61221209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 61221209 - 2⁸ = 61220953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (61221203) 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 7 ways as a sum of consecutive naturals, for example, 8519 + ... + 13964.

It is an arithmetic number, because the mean of its divisors is an integer number (8768760).

Almost surely, 2^61221209 is an apocalyptic number.

It is an amenable number.

61221209 is a deficient number, since it is larger than the sum of its proper divisors (8928871).

61221209 is a wasteful number, since it uses less digits than its factorization.

61221209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22879.

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 61221209 is about 7824.3983155256. The cubic root of 61221209 is about 394.1249850415.

The spelling of 61221209 in words is "sixty-one million, two hundred twenty-one thousand, two hundred nine".