1205999399 has 4 divisors (see below), whose sum is σ = 1315635720. Its totient is φ = 1096363080.

The previous prime is 1205999383. The next prime is 1205999413. The reversal of 1205999399 is 9939995021.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1205999399 - 2⁴ = 1205999383 is a prime.

It is a super-2 number, since 2×1205999399² = 2908869100776722402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1205999309) 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, 54818144 + ... + 54818165.

It is an arithmetic number, because the mean of its divisors is an integer number (328908930).

Almost surely, 2^1205999399 is an apocalyptic number.

1205999399 is a deficient number, since it is larger than the sum of its proper divisors (109636321).

1205999399 is a wasteful number, since it uses less digits than its factorization.

1205999399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109636320.

The product of its (nonzero) digits is 1771470, while the sum is 56.

The square root of 1205999399 is about 34727.5020552875. The cubic root of 1205999399 is about 1064.4265463248.

The spelling of 1205999399 in words is "one billion, two hundred five million, nine hundred ninety-nine thousand, three hundred ninety-nine".