1581216097 has 8 divisors (see below), whose sum is σ = 1654122600. Its totient is φ = 1509535104.

The previous prime is 1581216073. The next prime is 1581216103. The reversal of 1581216097 is 7906121851.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 40401 + 1581175696 = 201^2 + 39764^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1581216097 - 2¹¹ = 1581214049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1581216017) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 303738 + ... + 308899.

It is an arithmetic number, because the mean of its divisors is an integer number (206765325).

Almost surely, 2^1581216097 is an apocalyptic number.

It is an amenable number.

1581216097 is a deficient number, since it is larger than the sum of its proper divisors (72906503).

1581216097 is an equidigital number, since it uses as much as digits as its factorization.

1581216097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 612755.

The product of its (nonzero) digits is 30240, while the sum is 40.

The square root of 1581216097 is about 39764.5080065125. The cubic root of 1581216097 is about 1165.0120273584.

The spelling of 1581216097 in words is "one billion, five hundred eighty-one million, two hundred sixteen thousand, ninety-seven".