61221612216 has 64 divisors (see below), whose sum is σ = 157278823200. Its totient is φ = 19844517888.

The previous prime is 61221612211. The next prime is 61221612217.

61221612216 is nontrivially palindromic in base 10.

It is a super-3 number, since 3×61221612216³ (a number of 33 digits) contains 333 as substring.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61221612211) 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 15 ways as a sum of consecutive naturals, for example, 1644820 + ... + 1681628.

Almost surely, 2^61221612216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 61221612216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78639411600).

61221612216 is an abundant number, since it is smaller than the sum of its proper divisors (96057210984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

61221612216 is a wasteful number, since it uses less digits than its factorization.

61221612216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38728 (or 38724 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The spelling of 61221612216 in words is "sixty-one billion, two hundred twenty-one million, six hundred twelve thousand, two hundred sixteen".