168819421 has 2 divisors, whose sum is σ = 168819422. Its totient is φ = 168819420.

The previous prime is 168819403. The next prime is 168819457. The reversal of 168819421 is 124918861.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138415225 + 30404196 = 11765^2 + 5514^2 .

It is a cyclic number.

It is not a de Polignac number, because 168819421 - 2⁷ = 168819293 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168819821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84409710 + 84409711.

It is an arithmetic number, because the mean of its divisors is an integer number (84409711).

Almost surely, 2^168819421 is an apocalyptic number.

It is an amenable number.

168819421 is a deficient number, since it is larger than the sum of its proper divisors (1).

168819421 is an equidigital number, since it uses as much as digits as its factorization.

168819421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27648, while the sum is 40.

The square root of 168819421 is about 12993.0527975530. The cubic root of 168819421 is about 552.6804919333.

The spelling of 168819421 in words is "one hundred sixty-eight million, eight hundred nineteen thousand, four hundred twenty-one".