2159821154689 has 81 divisors (see below), whose sum is σ = 2621514463113. Its totient is φ = 1777668076800.

The previous prime is 2159821154657. The next prime is 2159821154707. The reversal of 2159821154689 is 9864511289512.

The square root of 2159821154689 is 1469633.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 213494823025 + 1946326331664 = 462055^2 + 1395108^2 .

It is not a de Polignac number, because 2159821154689 - 2⁵ = 2159821154657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2159821154089) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 7969819624 + ... + 7969819894.

Almost surely, 2^{2159821154689} is an apocalyptic number.

2159821154689 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

2159821154689 is the 1469633-rd square number.

2159821154689 is the 734817-th centered octagonal number.

It is an amenable number.

2159821154689 is a deficient number, since it is larger than the sum of its proper divisors (461693308424).

2159821154689 is an equidigital number, since it uses as much as digits as its factorization.

2159821154689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656 (or 328 counting only the distinct ones).

The product of its digits is 12441600, while the sum is 61.

The spelling of 2159821154689 in words is "two trillion, one hundred fifty-nine billion, eight hundred twenty-one million, one hundred fifty-four thousand, six hundred eighty-nine".