105651566021 has 4 divisors (see below), whose sum is σ = 109294723500. Its totient is φ = 102008408544.

The previous prime is 105651565993. The next prime is 105651566029. The reversal of 105651566021 is 120665156501.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120665156501 = 107 ⋅1127711743.

It can be written as a sum of positive squares in 2 ways, for example, as 32880568900 + 72770997121 = 181330^2 + 269761^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-105651566021 is a prime.

It is a super-2 number, since 2×105651566021² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (105651566029) 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, 1821578696 + ... + 1821578753.

It is an arithmetic number, because the mean of its divisors is an integer number (27323680875).

Almost surely, 2^105651566021 is an apocalyptic number.

It is an amenable number.

105651566021 is a deficient number, since it is larger than the sum of its proper divisors (3643157479).

105651566021 is an equidigital number, since it uses as much as digits as its factorization.

105651566021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3643157478.

The product of its (nonzero) digits is 54000, while the sum is 38.

The spelling of 105651566021 in words is "one hundred five billion, six hundred fifty-one million, five hundred sixty-six thousand, twenty-one".