1221053545 has 4 divisors (see below), whose sum is σ = 1465264260. Its totient is φ = 976842832.

The previous prime is 1221053521. The next prime is 1221053573. The reversal of 1221053545 is 5453501221.

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

It can be written as a sum of positive squares in 2 ways, for example, as 218951209 + 1002102336 = 14797^2 + 31656^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221053545 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 122105350 + ... + 122105359.

It is an arithmetic number, because the mean of its divisors is an integer number (366316065).

Almost surely, 2^1221053545 is an apocalyptic number.

It is an amenable number.

1221053545 is a deficient number, since it is larger than the sum of its proper divisors (244210715).

1221053545 is an equidigital number, since it uses as much as digits as its factorization.

1221053545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244210714.

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 1221053545 is about 34943.5765914138. The cubic root of 1221053545 is about 1068.8372220232.

Adding to 1221053545 its reverse (5453501221), we get a palindrome (6674554766).

The spelling of 1221053545 in words is "one billion, two hundred twenty-one million, fifty-three thousand, five hundred forty-five".