164067821 has 4 divisors (see below), whose sum is σ = 164146944. Its totient is φ = 163988700.

The previous prime is 164067817. The next prime is 164067823. The reversal of 164067821 is 128760461.

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, and also an emirpimes, since its reverse is a distinct semiprime: 128760461 = 521 ⋅247141.

It is a cyclic number.

It is not a de Polignac number, because 164067821 - 2² = 164067817 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 (164067823) 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, 36365 + ... + 40626.

It is an arithmetic number, because the mean of its divisors is an integer number (41036736).

Almost surely, 2^164067821 is an apocalyptic number.

It is an amenable number.

164067821 is a deficient number, since it is larger than the sum of its proper divisors (79123).

164067821 is an equidigital number, since it uses as much as digits as its factorization.

164067821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79122.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 164067821 is about 12808.8961663369. The cubic root of 164067821 is about 547.4458107512.

The spelling of 164067821 in words is "one hundred sixty-four million, sixty-seven thousand, eight hundred twenty-one".