169890421 has 4 divisors (see below), whose sum is σ = 174482092. Its totient is φ = 165298752.

The previous prime is 169890407. The next prime is 169890431. The reversal of 169890421 is 124098961.

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 122899396 + 46991025 = 11086^2 + 6855^2 .

It is a cyclic number.

It is not a de Polignac number, because 169890421 - 2⁵ = 169890389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (169890431) 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 in 3 ways as a sum of consecutive naturals, for example, 2295780 + ... + 2295853.

It is an arithmetic number, because the mean of its divisors is an integer number (43620523).

Almost surely, 2^169890421 is an apocalyptic number.

It is an amenable number.

169890421 is a deficient number, since it is larger than the sum of its proper divisors (4591671).

169890421 is an equidigital number, since it uses as much as digits as its factorization.

169890421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4591670.

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 169890421 is about 13034.2019702013. The cubic root of 169890421 is about 553.8467745606.

The spelling of 169890421 in words is "one hundred sixty-nine million, eight hundred ninety thousand, four hundred twenty-one".