2156561505 has 24 divisors (see below), whose sum is σ = 4272046272. Its totient is φ = 985856544.

The previous prime is 2156561479. The next prime is 2156561551. The reversal of 2156561505 is 5051656512.

It is not a de Polignac number, because 2156561505 - 2⁶ = 2156561441 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2156561505.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3422799 + ... + 3423428.

It is an arithmetic number, because the mean of its divisors is an integer number (178001928).

Almost surely, 2^2156561505 is an apocalyptic number.

It is an amenable number.

2156561505 is a deficient number, since it is larger than the sum of its proper divisors (2115484767).

2156561505 is a wasteful number, since it uses less digits than its factorization.

2156561505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6846245 (or 6846242 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 36.

The square root of 2156561505 is about 46438.7931044725. The cubic root of 2156561505 is about 1291.9745226008.

The spelling of 2156561505 in words is "two billion, one hundred fifty-six million, five hundred sixty-one thousand, five hundred five".