1581215 has 4 divisors (see below), whose sum is σ = 1897464. Its totient is φ = 1264968.

The previous prime is 1581211. The next prime is 1581257. The reversal of 1581215 is 5121851.

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 1581215 - 2² = 1581211 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1581211) 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, 158117 + ... + 158126.

It is an arithmetic number, because the mean of its divisors is an integer number (474366).

2^1581215 is an apocalyptic number.

1581215 is a deficient number, since it is larger than the sum of its proper divisors (316249).

1581215 is an equidigital number, since it uses as much as digits as its factorization.

1581215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316248.

The product of its digits is 400, while the sum is 23.

The square root of 1581215 is about 1257.4637171704. The cubic root of 1581215 is about 116.5011757942.

The spelling of 1581215 in words is "one million, five hundred eighty-one thousand, two hundred fifteen".