1201306561 has 16 divisors (see below), whose sum is σ = 1479729664. Its totient is φ = 949713984.

The previous prime is 1201306541. The next prime is 1201306573. The reversal of 1201306561 is 1656031021.

It is a cyclic number.

It is not a de Polignac number, because 1201306561 - 2⁵ = 1201306529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1201306501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 124855 + ... + 134131.

It is an arithmetic number, because the mean of its divisors is an integer number (92483104).

Almost surely, 2^1201306561 is an apocalyptic number.

It is an amenable number.

1201306561 is a deficient number, since it is larger than the sum of its proper divisors (278423103).

1201306561 is a wasteful number, since it uses less digits than its factorization.

1201306561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10720.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 1201306561 is about 34659.8696044864. The cubic root of 1201306561 is about 1063.0441038049.

Adding to 1201306561 its reverse (1656031021), we get a palindrome (2857337582).

The spelling of 1201306561 in words is "one billion, two hundred one million, three hundred six thousand, five hundred sixty-one".