1215543 has 12 divisors (see below), whose sum is σ = 1885560. Its totient is φ = 694512.

The previous prime is 1215521. The next prime is 1215553. The reversal of 1215543 is 3455121.

It is not a de Polignac number, because 1215543 - 2¹⁰ = 1214519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1215553) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3988 + ... + 4281.

It is an arithmetic number, because the mean of its divisors is an integer number (157130).

2^1215543 is an apocalyptic number.

1215543 is a deficient number, since it is larger than the sum of its proper divisors (670017).

1215543 is an equidigital number, since it uses as much as digits as its factorization.

1215543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8286 (or 8279 counting only the distinct ones).

The product of its digits is 600, while the sum is 21.

The square root of 1215543 is about 1102.5166665407. The cubic root of 1215543 is about 106.7226930064.

The spelling of 1215543 in words is "one million, two hundred fifteen thousand, five hundred forty-three".