169910021 has 2 divisors, whose sum is σ = 169910022. Its totient is φ = 169910020.

The previous prime is 169910017. The next prime is 169910023. The reversal of 169910021 is 120019961.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152152225 + 17757796 = 12335^2 + 4214^2 .

It is a cyclic number.

It is not a de Polignac number, because 169910021 - 2² = 169910017 is a prime.

It is a Sophie Germain prime.

Together with 169910023, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (169910023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84955010 + 84955011.

It is an arithmetic number, because the mean of its divisors is an integer number (84955011).

Almost surely, 2^169910021 is an apocalyptic number.

It is an amenable number.

169910021 is a deficient number, since it is larger than the sum of its proper divisors (1).

169910021 is an equidigital number, since it uses as much as digits as its factorization.

169910021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 29.

The square root of 169910021 is about 13034.9538165657. The cubic root of 169910021 is about 553.8680725621.

Adding to 169910021 its reverse (120019961), we get a palindrome (289929982).

The spelling of 169910021 in words is "one hundred sixty-nine million, nine hundred ten thousand, twenty-one".