21581463820161 has 8 divisors (see below), whose sum is σ = 32886040106944. Its totient is φ = 12332265040080.

The previous prime is 21581463820097. The next prime is 21581463820177. The reversal of 21581463820161 is 16102836418512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21581463820161 - 2⁶ = 21581463820097 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21581463820161.

It is not an unprimeable number, because it can be changed into a prime (21581463820181) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 513844376650 + ... + 513844376691.

It is an arithmetic number, because the mean of its divisors is an integer number (4110755013368).

Almost surely, 2^{21581463820161} is an apocalyptic number.

21581463820161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21581463820161 is a deficient number, since it is larger than the sum of its proper divisors (11304576286783).

21581463820161 is a wasteful number, since it uses less digits than its factorization.

21581463820161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1027688753351.

The product of its (nonzero) digits is 552960, while the sum is 48.

The spelling of 21581463820161 in words is "twenty-one trillion, five hundred eighty-one billion, four hundred sixty-three million, eight hundred twenty thousand, one hundred sixty-one".