1215531 has 6 divisors (see below), whose sum is σ = 1755780. Its totient is φ = 810348.

The previous prime is 1215521. The next prime is 1215553. The reversal of 1215531 is 1355121.

It is not a de Polignac number, because 1215531 - 2⁵ = 1215499 is a prime.

It is a super-2 number, since 2×1215531² = 2955031223922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1215521) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67521 + ... + 67538.

It is an arithmetic number, because the mean of its divisors is an integer number (292630).

2^1215531 is an apocalyptic number.

1215531 is a deficient number, since it is larger than the sum of its proper divisors (540249).

1215531 is a wasteful number, since it uses less digits than its factorization.

1215531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135065 (or 135062 counting only the distinct ones).

The product of its digits is 150, while the sum is 18.

The square root of 1215531 is about 1102.5112244327. The cubic root of 1215531 is about 106.7223418118.

The spelling of 1215531 in words is "one million, two hundred fifteen thousand, five hundred thirty-one".