1245204561 has 4 divisors (see below), whose sum is σ = 1660272752. Its totient is φ = 830136372.

The previous prime is 1245204547. The next prime is 1245204589. The reversal of 1245204561 is 1654025421.

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 not a de Polignac number, because 1245204561 - 2¹⁸ = 1244942417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1245204361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207534091 + ... + 207534096.

It is an arithmetic number, because the mean of its divisors is an integer number (415068188).

Almost surely, 2^1245204561 is an apocalyptic number.

It is an amenable number.

1245204561 is a deficient number, since it is larger than the sum of its proper divisors (415068191).

1245204561 is an equidigital number, since it uses as much as digits as its factorization.

1245204561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 415068190.

The product of its (nonzero) digits is 9600, while the sum is 30.

The square root of 1245204561 is about 35287.4561423744. The cubic root of 1245204561 is about 1075.8380516734.

Adding to 1245204561 its reverse (1654025421), we get a palindrome (2899229982).

The spelling of 1245204561 in words is "one billion, two hundred forty-five million, two hundred four thousand, five hundred sixty-one".