12651781 has 2 divisors, whose sum is σ = 12651782. Its totient is φ = 12651780.

The previous prime is 12651767. The next prime is 12651797. The reversal of 12651781 is 18715621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11282881 + 1368900 = 3359^2 + 1170^2 .

It is a cyclic number.

It is not a de Polignac number, because 12651781 - 2¹¹ = 12649733 is a prime.

It is a super-2 number, since 2×12651781² = 320135124943922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12651731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6325890 + 6325891.

It is an arithmetic number, because the mean of its divisors is an integer number (6325891).

Almost surely, 2^12651781 is an apocalyptic number.

It is an amenable number.

12651781 is a deficient number, since it is larger than the sum of its proper divisors (1).

12651781 is an equidigital number, since it uses as much as digits as its factorization.

12651781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3360, while the sum is 31.

The square root of 12651781 is about 3556.9342136171. The cubic root of 12651781 is about 233.0150051429.

The spelling of 12651781 in words is "twelve million, six hundred fifty-one thousand, seven hundred eighty-one".