101666399 has 2 divisors, whose sum is σ = 101666400. Its totient is φ = 101666398.

The previous prime is 101666393. The next prime is 101666401. The reversal of 101666399 is 993666101.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 101666399 - 2²⁴ = 84889183 is a prime.

Together with 101666401, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (101666393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50833199 + 50833200.

It is an arithmetic number, because the mean of its divisors is an integer number (50833200).

Almost surely, 2^101666399 is an apocalyptic number.

101666399 is a deficient number, since it is larger than the sum of its proper divisors (1).

101666399 is an equidigital number, since it uses as much as digits as its factorization.

101666399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 52488, while the sum is 41.

The square root of 101666399 is about 10082.9757016468. The cubic root of 101666399 is about 466.7229395293.

The spelling of 101666399 in words is "one hundred one million, six hundred sixty-six thousand, three hundred ninety-nine".