1200002561 has 2 divisors, whose sum is σ = 1200002562. Its totient is φ = 1200002560.

The previous prime is 1200002497. The next prime is 1200002581. The reversal of 1200002561 is 1652000021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 622801936 + 577200625 = 24956^2 + 24025^2 .

It is a cyclic number.

It is not a de Polignac number, because 1200002561 - 2⁶ = 1200002497 is a prime.

It is a super-2 number, since 2×1200002561² = 2880012292813117442, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1200002581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 600001280 + 600001281.

It is an arithmetic number, because the mean of its divisors is an integer number (600001281).

Almost surely, 2^1200002561 is an apocalyptic number.

It is an amenable number.

1200002561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1200002561 is an equidigital number, since it uses as much as digits as its factorization.

1200002561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 1200002561 is about 34641.0531162088. The cubic root of 1200002561 is about 1062.6593251456.

Adding to 1200002561 its reverse (1652000021), we get a palindrome (2852002582).

The spelling of 1200002561 in words is "one billion, two hundred million, two thousand, five hundred sixty-one".