21994627364649 has 9 divisors (see below), whose sum is σ = 31770037627159. Its totient is φ = 14663075530080.

The previous prime is 21994627364623. The next prime is 21994627364651. The reversal of 21994627364649 is 94646372649912.

The square root of 21994627364649 is 4689843.

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

21994627364649 is a `hidden beast` number, since 2 + 1 + 9 + 94 + 6 + 2 + 73 + 6 + 464 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2604695804649 + 19389931560000 = 1613907^2 + 4403400^2 .

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

It is not a de Polignac number, because 21994627364649 - 2⁵ = 21994627364617 is a prime.

It is a super-2 number, since 2×21994627364649² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21994629364649) 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, 13287889 + ... + 14851169.

Almost surely, 2^{21994627364649} is an apocalyptic number.

21994627364649 is the 4689843-rd square number.

21994627364649 is the 2344922-nd centered octagonal number.

It is an amenable number.

21994627364649 is a deficient number, since it is larger than the sum of its proper divisors (9775410262510).

21994627364649 is an frugal number, since it uses more digits than its factorization.

21994627364649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3126568 (or 1563284 counting only the distinct ones).

The product of its digits is 846526464, while the sum is 72.

The spelling of 21994627364649 in words is "twenty-one trillion, nine hundred ninety-four billion, six hundred twenty-seven million, three hundred sixty-four thousand, six hundred forty-nine".