166121643 has 4 divisors (see below), whose sum is σ = 221495528. Its totient is φ = 110747760.

The previous prime is 166121633. The next prime is 166121689. The reversal of 166121643 is 346121661.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 166121643 - 2¹² = 166117547 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 166121643.

It is not an unprimeable number, because it can be changed into a prime (166121633) 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, 27686938 + ... + 27686943.

It is an arithmetic number, because the mean of its divisors is an integer number (55373882).

Almost surely, 2^166121643 is an apocalyptic number.

166121643 is a deficient number, since it is larger than the sum of its proper divisors (55373885).

166121643 is an equidigital number, since it uses as much as digits as its factorization.

166121643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55373884.

The product of its digits is 5184, while the sum is 30.

The square root of 166121643 is about 12888.8185261489. The cubic root of 166121643 is about 549.7206768997.

The spelling of 166121643 in words is "one hundred sixty-six million, one hundred twenty-one thousand, six hundred forty-three".