1205005663 has 4 divisors (see below), whose sum is σ = 1206133960. Its totient is φ = 1203877368.

The previous prime is 1205005661. The next prime is 1205005687. The reversal of 1205005663 is 3665005021.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3665005021 = 83 ⋅44156687.

It is a cyclic number.

It is not a de Polignac number, because 1205005663 - 2¹ = 1205005661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205005661) 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, 562545 + ... + 564682.

It is an arithmetic number, because the mean of its divisors is an integer number (301533490).

Almost surely, 2^1205005663 is an apocalyptic number.

1205005663 is a deficient number, since it is larger than the sum of its proper divisors (1128297).

1205005663 is a wasteful number, since it uses less digits than its factorization.

1205005663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1128296.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 1205005663 is about 34713.1914839301. The cubic root of 1205005663 is about 1064.1341057035.

The spelling of 1205005663 in words is "one billion, two hundred five million, five thousand, six hundred sixty-three".