1213217543 has 4 divisors (see below), whose sum is σ = 1213934160. Its totient is φ = 1212500928.

The previous prime is 1213217539. The next prime is 1213217549. The reversal of 1213217543 is 3457123121.

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 1213217543 - 2² = 1213217539 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 (1213217549) 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, 355763 + ... + 359156.

It is an arithmetic number, because the mean of its divisors is an integer number (303483540).

Almost surely, 2^1213217543 is an apocalyptic number.

1213217543 is a deficient number, since it is larger than the sum of its proper divisors (716617).

1213217543 is an equidigital number, since it uses as much as digits as its factorization.

1213217543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 716616.

The product of its digits is 5040, while the sum is 29.

The square root of 1213217543 is about 34831.2724860864. The cubic root of 1213217543 is about 1066.5459244949.

The spelling of 1213217543 in words is "one billion, two hundred thirteen million, two hundred seventeen thousand, five hundred forty-three".