2161604403256 has 32 divisors (see below), whose sum is σ = 4240199638080. Its totient is φ = 1032006246400.

The previous prime is 2161604403239. The next prime is 2161604403271. The reversal of 2161604403256 is 6523044061612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 70093705 + ... + 70124536.

It is an arithmetic number, because the mean of its divisors is an integer number (132506238690).

Almost surely, 2^{2161604403256} is an apocalyptic number.

It is an amenable number.

2161604403256 is a deficient number, since it is larger than the sum of its proper divisors (2078595234824).

2161604403256 is a wasteful number, since it uses less digits than its factorization.

2161604403256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140218335 (or 140218331 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 40.

Adding to 2161604403256 its reverse (6523044061612), we get a palindrome (8684648464868).

The spelling of 2161604403256 in words is "two trillion, one hundred sixty-one billion, six hundred four million, four hundred three thousand, two hundred fifty-six".