21677246509689 has 9 divisors (see below), whose sum is σ = 31311598467279. Its totient is φ = 14451488361360.

The previous prime is 21677246509687. The next prime is 21677246509691. The reversal of 21677246509689 is 98690564277612.

The square root of 21677246509689 is 4655883.

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

21677246509689 is a `hidden beast` number, since 2 + 1 + 6 + 7 + 72 + 46 + 509 + 6 + 8 + 9 = 666.

It is an interprime number because it is at equal distance from previous prime (21677246509687) and next prime (21677246509691).

It can be written as a sum of positive squares in only one way, i.e., 21569215967289 + 108030542400 = 4644267^2 + 328680^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 21677246509689 - 2¹ = 21677246509687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21677246509687) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 13191669 + ... + 14743629.

Almost surely, 2^{21677246509689} is an apocalyptic number.

21677246509689 is the 4655883-rd square number.

21677246509689 is the 2327942-nd centered octagonal number.

It is an amenable number.

21677246509689 is a deficient number, since it is larger than the sum of its proper divisors (9634351957590).

21677246509689 is an frugal number, since it uses more digits than its factorization.

21677246509689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3103928 (or 1551964 counting only the distinct ones).

The product of its (nonzero) digits is 548674560, while the sum is 72.

The spelling of 21677246509689 in words is "twenty-one trillion, six hundred seventy-seven billion, two hundred forty-six million, five hundred nine thousand, six hundred eighty-nine".