161285639 has 2 divisors, whose sum is σ = 161285640. Its totient is φ = 161285638.

The previous prime is 161285633. The next prime is 161285693. The reversal of 161285639 is 936582161.

Together with next prime (161285693) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161285639 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 161285596 and 161285605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161285633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80642819 + 80642820.

It is an arithmetic number, because the mean of its divisors is an integer number (80642820).

Almost surely, 2^161285639 is an apocalyptic number.

161285639 is a deficient number, since it is larger than the sum of its proper divisors (1).

161285639 is an equidigital number, since it uses as much as digits as its factorization.

161285639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 77760, while the sum is 41.

The square root of 161285639 is about 12699.8283059260. The cubic root of 161285639 is about 544.3337131632. Note that the first 3 decimals are identical.

The spelling of 161285639 in words is "one hundred sixty-one million, two hundred eighty-five thousand, six hundred thirty-nine".