166537643 has 4 divisors (see below), whose sum is σ = 166797288. Its totient is φ = 166278000.

The previous prime is 166537619. The next prime is 166537669. The reversal of 166537643 is 346735661.

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

It is a cyclic number.

It is not a de Polignac number, because 166537643 - 2¹⁶ = 166472107 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 166537643.

It is not an unprimeable number, because it can be changed into a prime (166539643) 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, 128858 + ... + 130143.

It is an arithmetic number, because the mean of its divisors is an integer number (41699322).

Almost surely, 2^166537643 is an apocalyptic number.

166537643 is a deficient number, since it is larger than the sum of its proper divisors (259645).

166537643 is an equidigital number, since it uses as much as digits as its factorization.

166537643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259644.

The product of its digits is 272160, while the sum is 41.

The square root of 166537643 is about 12904.9464547514. The cubic root of 166537643 is about 550.1791625681.

The spelling of 166537643 in words is "one hundred sixty-six million, five hundred thirty-seven thousand, six hundred forty-three".