1218572549 has 4 divisors (see below), whose sum is σ = 1221788160. Its totient is φ = 1215356940.

The previous prime is 1218572533. The next prime is 1218572557. The reversal of 1218572549 is 9452758121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1218572549 - 2⁴ = 1218572533 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 (1218572519) 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, 1607237 + ... + 1607994.

It is an arithmetic number, because the mean of its divisors is an integer number (305447040).

Almost surely, 2^1218572549 is an apocalyptic number.

It is an amenable number.

1218572549 is a deficient number, since it is larger than the sum of its proper divisors (3215611).

1218572549 is an equidigital number, since it uses as much as digits as its factorization.

1218572549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3215610.

The product of its digits is 201600, while the sum is 44.

The square root of 1218572549 is about 34908.0585108940. The cubic root of 1218572549 is about 1068.1128260240.

It can be divided in two parts, 1218572 and 549, that added together give a palindrome (1219121).

The spelling of 1218572549 in words is "one billion, two hundred eighteen million, five hundred seventy-two thousand, five hundred forty-nine".