61536220221 has 24 divisors (see below), whose sum is σ = 95479379424. Its totient is φ = 35150495520.

The previous prime is 61536220171. The next prime is 61536220223. The reversal of 61536220221 is 12202263516.

It is not a de Polignac number, because 61536220221 - 2⁹ = 61536219709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61536220223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 326566 + ... + 479288.

It is an arithmetic number, because the mean of its divisors is an integer number (3978307476).

Almost surely, 2^61536220221 is an apocalyptic number.

It is an amenable number.

61536220221 is a deficient number, since it is larger than the sum of its proper divisors (33943159203).

61536220221 is a wasteful number, since it uses less digits than its factorization.

61536220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155481 (or 155474 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

Adding to 61536220221 its reverse (12202263516), we get a palindrome (73738483737).

The spelling of 61536220221 in words is "sixty-one billion, five hundred thirty-six million, two hundred twenty thousand, two hundred twenty-one".