1566240121 has 4 divisors (see below), whose sum is σ = 1568419200. Its totient is φ = 1564061044.

The previous prime is 1566240097. The next prime is 1566240157. The reversal of 1566240121 is 1210426651.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1566240121 - 2⁵ = 1566240089 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1566240121.

It is not an unprimeable number, because it can be changed into a prime (1566241121) 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, 1088461 + ... + 1089898.

It is an arithmetic number, because the mean of its divisors is an integer number (392104800).

Almost surely, 2^1566240121 is an apocalyptic number.

It is an amenable number.

1566240121 is a deficient number, since it is larger than the sum of its proper divisors (2179079).

1566240121 is an equidigital number, since it uses as much as digits as its factorization.

1566240121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2179078.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 1566240121 is about 39575.7516795323. The cubic root of 1566240121 is about 1161.3223428440.

Adding to 1566240121 its reverse (1210426651), we get a palindrome (2776666772).

The spelling of 1566240121 in words is "one billion, five hundred sixty-six million, two hundred forty thousand, one hundred twenty-one".