21146747161 has 4 divisors (see below), whose sum is σ = 21662521524. Its totient is φ = 20630972800.

The previous prime is 21146747143. The next prime is 21146747183. The reversal of 21146747161 is 16174764112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4794731536 + 16352015625 = 69244^2 + 127875^2 .

It is a cyclic number.

It is not a de Polignac number, because 21146747161 - 2¹³ = 21146738969 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21146787161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 257887120 + ... + 257887201.

It is an arithmetic number, because the mean of its divisors is an integer number (5415630381).

Almost surely, 2^21146747161 is an apocalyptic number.

It is an amenable number.

21146747161 is a deficient number, since it is larger than the sum of its proper divisors (515774363).

21146747161 is an equidigital number, since it uses as much as digits as its factorization.

21146747161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515774362.

The product of its digits is 56448, while the sum is 40.

The spelling of 21146747161 in words is "twenty-one billion, one hundred forty-six million, seven hundred forty-seven thousand, one hundred sixty-one".