164226056821 has 4 divisors (see below), whose sum is σ = 168231570444. Its totient is φ = 160220543200.

The previous prime is 164226056809. The next prime is 164226056873. The reversal of 164226056821 is 128650622461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128650622461 = 929 ⋅138482909.

It can be written as a sum of positive squares in 2 ways, for example, as 52610596900 + 111615459921 = 229370^2 + 334089^2 .

It is a cyclic number.

It is not a de Polignac number, because 164226056821 - 2²⁵ = 164192502389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (164226056801) 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, 2002756750 + ... + 2002756831.

It is an arithmetic number, because the mean of its divisors is an integer number (42057892611).

Almost surely, 2^164226056821 is an apocalyptic number.

It is an amenable number.

164226056821 is a deficient number, since it is larger than the sum of its proper divisors (4005513623).

164226056821 is an equidigital number, since it uses as much as digits as its factorization.

164226056821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4005513622.

The product of its (nonzero) digits is 276480, while the sum is 43.

The spelling of 164226056821 in words is "one hundred sixty-four billion, two hundred twenty-six million, fifty-six thousand, eight hundred twenty-one".