216864021641 has 4 divisors (see below), whose sum is σ = 216945216384. Its totient is φ = 216782826900.

The previous prime is 216864021637. The next prime is 216864021643. The reversal of 216864021641 is 146120468612.

216864021641 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 216864021641 - 2² = 216864021637 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216864021643) 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 3 ways as a sum of consecutive naturals, for example, 40593365 + ... + 40598706.

It is an arithmetic number, because the mean of its divisors is an integer number (54236304096).

Almost surely, 2^216864021641 is an apocalyptic number.

It is an amenable number.

216864021641 is a deficient number, since it is larger than the sum of its proper divisors (81194743).

216864021641 is an equidigital number, since it uses as much as digits as its factorization.

216864021641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81194742.

The product of its (nonzero) digits is 110592, while the sum is 41.

The spelling of 216864021641 in words is "two hundred sixteen billion, eight hundred sixty-four million, twenty-one thousand, six hundred forty-one".