12805649 has 6 divisors (see below), whose sum is σ = 12948534. Its totient is φ = 12664320.

The previous prime is 12805627. The next prime is 12805673. The reversal of 12805649 is 94650821.

12805649 = T₂₆₂ + T₂₆₃ + ... + T₄₅₅.

It can be written as a sum of positive squares in 3 ways, for example, as 330625 + 12475024 = 575^2 + 3532^2 .

It is not a de Polignac number, because 12805649 - 2¹⁶ = 12740113 is a prime.

It is a super-2 number, since 2×12805649² = 327969292622402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12805609) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8729 + ... + 10089.

It is an arithmetic number, because the mean of its divisors is an integer number (2158089).

Almost surely, 2^12805649 is an apocalyptic number.

It is an amenable number.

12805649 is a deficient number, since it is larger than the sum of its proper divisors (142885).

12805649 is an frugal number, since it uses more digits than its factorization.

12805649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1555 (or 1458 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 12805649 is about 3578.4981486652. The cubic root of 12805649 is about 233.9558260297.

The spelling of 12805649 in words is "twelve million, eight hundred five thousand, six hundred forty-nine".