1245031561 has 4 divisors (see below), whose sum is σ = 1299163392. Its totient is φ = 1190899732.

The previous prime is 1245031553. The next prime is 1245031597. The reversal of 1245031561 is 1651305421.

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 1245031561 - 2³ = 1245031553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1245031531) 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, 27065881 + ... + 27065926.

It is an arithmetic number, because the mean of its divisors is an integer number (324790848).

Almost surely, 2^1245031561 is an apocalyptic number.

It is an amenable number.

1245031561 is a deficient number, since it is larger than the sum of its proper divisors (54131831).

1245031561 is an equidigital number, since it uses as much as digits as its factorization.

1245031561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54131830.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 1245031561 is about 35285.0047612297. The cubic root of 1245031561 is about 1075.7882262314.

Adding to 1245031561 its reverse (1651305421), we get a palindrome (2896336982).

The spelling of 1245031561 in words is "one billion, two hundred forty-five million, thirty-one thousand, five hundred sixty-one".