164197661 has 4 divisors (see below), whose sum is σ = 168202524. Its totient is φ = 160192800.

The previous prime is 164197633. The next prime is 164197673. The reversal of 164197661 is 166791461.

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 12292036 + 151905625 = 3506^2 + 12325^2 .

It is a cyclic number.

It is not a de Polignac number, because 164197661 - 2¹⁸ = 163935517 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41), and also a Moran number because the ratio is a prime number: 4004821 = 164197661 / (1 + 6 + 4 + 1 + 9 + 7 + 6 + 6 + 1).

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 (164197861) 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, 2002370 + ... + 2002451.

It is an arithmetic number, because the mean of its divisors is an integer number (42050631).

Almost surely, 2^164197661 is an apocalyptic number.

It is an amenable number.

164197661 is a deficient number, since it is larger than the sum of its proper divisors (4004863).

164197661 is an equidigital number, since it uses as much as digits as its factorization.

164197661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4004862.

The product of its digits is 54432, while the sum is 41.

The square root of 164197661 is about 12813.9635164144. The cubic root of 164197661 is about 547.5901852368.

The spelling of 164197661 in words is "one hundred sixty-four million, one hundred ninety-seven thousand, six hundred sixty-one".