166139387 has 4 divisors (see below), whose sum is σ = 167067720. Its totient is φ = 165211056.

The previous prime is 166139381. The next prime is 166139437. The reversal of 166139387 is 783931661.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166139387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166139381) 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, 463898 + ... + 464255.

It is an arithmetic number, because the mean of its divisors is an integer number (41766930).

Almost surely, 2^166139387 is an apocalyptic number.

166139387 is a deficient number, since it is larger than the sum of its proper divisors (928333).

166139387 is an equidigital number, since it uses as much as digits as its factorization.

166139387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928332.

The product of its digits is 163296, while the sum is 44.

The square root of 166139387 is about 12889.5068563541. The cubic root of 166139387 is about 549.7402486951.

The spelling of 166139387 in words is "one hundred sixty-six million, one hundred thirty-nine thousand, three hundred eighty-seven".