1181531 has 4 divisors (see below), whose sum is σ = 1272432. Its totient is φ = 1090632.

The previous prime is 1181527. The next prime is 1181549. The reversal of 1181531 is 1351811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1351811 = 41 ⋅32971.

It is a cyclic number.

It is not a de Polignac number, because 1181531 - 2² = 1181527 is a prime.

It is a super-2 number, since 2×1181531² = 2792031007922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1181501) 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, 45431 + ... + 45456.

It is an arithmetic number, because the mean of its divisors is an integer number (318108).

2^1181531 is an apocalyptic number.

1181531 is a deficient number, since it is larger than the sum of its proper divisors (90901).

1181531 is an equidigital number, since it uses as much as digits as its factorization.

1181531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90900.

The product of its digits is 120, while the sum is 20.

The square root of 1181531 is about 1086.9825205586. The cubic root of 1181531 is about 105.7178625003.

The spelling of 1181531 in words is "one million, one hundred eighty-one thousand, five hundred thirty-one".