166859421 has 4 divisors (see below), whose sum is σ = 222479232. Its totient is φ = 111239612.

The previous prime is 166859419. The next prime is 166859449. The reversal of 166859421 is 124958661.

166859421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 124958661 = 3 ⋅41652887.

It is a cyclic number.

It is not a de Polignac number, because 166859421 - 2¹ = 166859419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166859491) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27809901 + ... + 27809906.

It is an arithmetic number, because the mean of its divisors is an integer number (55619808).

Almost surely, 2^166859421 is an apocalyptic number.

It is an amenable number.

166859421 is a deficient number, since it is larger than the sum of its proper divisors (55619811).

166859421 is an equidigital number, since it uses as much as digits as its factorization.

166859421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55619810.

The product of its digits is 103680, while the sum is 42.

The square root of 166859421 is about 12917.4076733685. The cubic root of 166859421 is about 550.5332800098.

It can be divided in two parts, 16685 and 9421, that added together give a triangular number (26106 = T₂₂₈).

The spelling of 166859421 in words is "one hundred sixty-six million, eight hundred fifty-nine thousand, four hundred twenty-one".