1261543199 has 16 divisors (see below), whose sum is σ = 1456006656. Its totient is φ = 1070690400.

The previous prime is 1261543163. The next prime is 1261543207. The reversal of 1261543199 is 9913451621.

It is a cyclic number.

It is not a de Polignac number, because 1261543199 - 2¹⁶ = 1261477663 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 (1261543139) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 339944 + ... + 343634.

It is an arithmetic number, because the mean of its divisors is an integer number (91000416).

Almost surely, 2^1261543199 is an apocalyptic number.

1261543199 is a deficient number, since it is larger than the sum of its proper divisors (194463457).

1261543199 is a wasteful number, since it uses less digits than its factorization.

1261543199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4166.

The product of its digits is 58320, while the sum is 41.

The square root of 1261543199 is about 35518.2094002499. The cubic root of 1261543199 is about 1080.5230659578.

The spelling of 1261543199 in words is "one billion, two hundred sixty-one million, five hundred forty-three thousand, one hundred ninety-nine".