1491531 has 4 divisors (see below), whose sum is σ = 1988712. Its totient is φ = 994352.

The previous prime is 1491521. The next prime is 1491547. The reversal of 1491531 is 1351941.

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 1491531 - 2⁷ = 1491403 is a prime.

It is a super-2 number, since 2×1491531² = 4449329447922, which contains 22 as substring.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (1491521) 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, 248586 + ... + 248591.

It is an arithmetic number, because the mean of its divisors is an integer number (497178).

2^1491531 is an apocalyptic number.

1491531 is a deficient number, since it is larger than the sum of its proper divisors (497181).

1491531 is an equidigital number, since it uses as much as digits as its factorization.

1491531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 497180.

The product of its digits is 540, while the sum is 24.

The square root of 1491531 is about 1221.2825225966. The cubic root of 1491531 is about 114.2555823092.

The spelling of 1491531 in words is "one million, four hundred ninety-one thousand, five hundred thirty-one".