1491581 has 16 divisors (see below), whose sum is σ = 1889664. Its totient is φ = 1145664.

The previous prime is 1491577. The next prime is 1491583. The reversal of 1491581 is 1851941.

It is not a de Polignac number, because 1491581 - 2² = 1491577 is a prime.

It is a super-3 number, since 3×1491581³ = 9955470333868427823, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1491583) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3146 + ... + 3588.

It is an arithmetic number, because the mean of its divisors is an integer number (118104).

2^1491581 is an apocalyptic number.

It is an amenable number.

1491581 is a deficient number, since it is larger than the sum of its proper divisors (398083).

1491581 is a wasteful number, since it uses less digits than its factorization.

1491581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 500.

The product of its digits is 1440, while the sum is 29.

The square root of 1491581 is about 1221.3029927090. The cubic root of 1491581 is about 114.2568590098.

The spelling of 1491581 in words is "one million, four hundred ninety-one thousand, five hundred eighty-one".