2161531409 has 8 divisors (see below), whose sum is σ = 2277644640. Its totient is φ = 2045653056.

The previous prime is 2161531381. The next prime is 2161531469. The reversal of 2161531409 is 9041351612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2161531409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2161531469) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39659 + ... + 76784.

It is an arithmetic number, because the mean of its divisors is an integer number (284705580).

Almost surely, 2^2161531409 is an apocalyptic number.

It is an amenable number.

2161531409 is a deficient number, since it is larger than the sum of its proper divisors (116113231).

2161531409 is a wasteful number, since it uses less digits than its factorization.

2161531409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117439.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 2161531409 is about 46492.2725729771. The cubic root of 2161531409 is about 1292.9662345059.

The spelling of 2161531409 in words is "two billion, one hundred sixty-one million, five hundred thirty-one thousand, four hundred nine".