1216531 has 4 divisors (see below), whose sum is σ = 1231272. Its totient is φ = 1201792.

The previous prime is 1216529. The next prime is 1216543. The reversal of 1216531 is 1356121.

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 1216531 - 2¹ = 1216529 is a prime.

It is a super-2 number, since 2×1216531² = 2959895347922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1216499 and 1216508.

It is not an unprimeable number, because it can be changed into a prime (1216561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7246 + ... + 7411.

It is an arithmetic number, because the mean of its divisors is an integer number (307818).

2^1216531 is an apocalyptic number.

1216531 is a deficient number, since it is larger than the sum of its proper divisors (14741).

1216531 is an equidigital number, since it uses as much as digits as its factorization.

1216531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14740.

The product of its digits is 180, while the sum is 19.

The square root of 1216531 is about 1102.9646413190. The cubic root of 1216531 is about 106.7516001055.

The spelling of 1216531 in words is "one million, two hundred sixteen thousand, five hundred thirty-one".