12781551 has 4 divisors (see below), whose sum is σ = 17042072. Its totient is φ = 8521032.

The previous prime is 12781541. The next prime is 12781553. The reversal of 12781551 is 15518721.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 12781551 - 2⁶ = 12781487 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12781553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2130256 + ... + 2130261.

It is an arithmetic number, because the mean of its divisors is an integer number (4260518).

Almost surely, 2^12781551 is an apocalyptic number.

12781551 is a deficient number, since it is larger than the sum of its proper divisors (4260521).

12781551 is an equidigital number, since it uses as much as digits as its factorization.

12781551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4260520.

The product of its digits is 2800, while the sum is 30.

The square root of 12781551 is about 3575.1295081437. The cubic root of 12781551 is about 233.8089791787.

The spelling of 12781551 in words is "twelve million, seven hundred eighty-one thousand, five hundred fifty-one".