2161639 has 2 divisors, whose sum is σ = 2161640. Its totient is φ = 2161638.

The previous prime is 2161637. The next prime is 2161697. The reversal of 2161639 is 9361612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2161639 - 2¹ = 2161637 is a prime.

Together with 2161637, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2161633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080819 + 1080820.

It is an arithmetic number, because the mean of its divisors is an integer number (1080820).

2^2161639 is an apocalyptic number.

2161639 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161639 is an equidigital number, since it uses as much as digits as its factorization.

2161639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1944, while the sum is 28.

The square root of 2161639 is about 1470.2513390574. The cubic root of 2161639 is about 129.2987686769.

The spelling of 2161639 in words is "two million, one hundred sixty-one thousand, six hundred thirty-nine".