1228636551 has 4 divisors (see below), whose sum is σ = 1638182072. Its totient is φ = 819091032.

The previous prime is 1228636537. The next prime is 1228636561. The reversal of 1228636551 is 1556368221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1556368221 = 3 ⋅518789407.

It is not a de Polignac number, because 1228636551 - 2⁹ = 1228636039 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 (1228636511) 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, 204772756 + ... + 204772761.

It is an arithmetic number, because the mean of its divisors is an integer number (409545518).

Almost surely, 2^1228636551 is an apocalyptic number.

1228636551 is a deficient number, since it is larger than the sum of its proper divisors (409545521).

1228636551 is an equidigital number, since it uses as much as digits as its factorization.

1228636551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409545520.

The product of its digits is 86400, while the sum is 39.

The square root of 1228636551 is about 35051.9122302907. The cubic root of 1228636551 is about 1071.0452275108.

The spelling of 1228636551 in words is "one billion, two hundred twenty-eight million, six hundred thirty-six thousand, five hundred fifty-one".