101664561 has 4 divisors (see below), whose sum is σ = 135552752. Its totient is φ = 67776372.

The previous prime is 101664557. The next prime is 101664571. The reversal of 101664561 is 165466101.

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.

It is not a de Polignac number, because 101664561 - 2² = 101664557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (101664551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16944091 + ... + 16944096.

It is an arithmetic number, because the mean of its divisors is an integer number (33888188).

Almost surely, 2^101664561 is an apocalyptic number.

It is an amenable number.

101664561 is a deficient number, since it is larger than the sum of its proper divisors (33888191).

101664561 is an equidigital number, since it uses as much as digits as its factorization.

101664561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33888190.

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 101664561 is about 10082.8845575063. The cubic root of 101664561 is about 466.7201269254.

The spelling of 101664561 in words is "one hundred one million, six hundred sixty-four thousand, five hundred sixty-one".