1566432421 has 4 divisors (see below), whose sum is σ = 1568119500. Its totient is φ = 1564745344.

The previous prime is 1566432379. The next prime is 1566432473. The reversal of 1566432421 is 1242346651.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 138650625 + 1427781796 = 11775^2 + 37786^2 .

It is a cyclic number.

It is not a de Polignac number, because 1566432421 - 2¹⁷ = 1566301349 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 (1566430421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 842146 + ... + 844003.

It is an arithmetic number, because the mean of its divisors is an integer number (392029875).

Almost surely, 2^1566432421 is an apocalyptic number.

It is an amenable number.

1566432421 is a deficient number, since it is larger than the sum of its proper divisors (1687079).

1566432421 is an equidigital number, since it uses as much as digits as its factorization.

1566432421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1687078.

The product of its digits is 34560, while the sum is 34.

The square root of 1566432421 is about 39578.1811229369. The cubic root of 1566432421 is about 1161.3698692193.

The spelling of 1566432421 in words is "one billion, five hundred sixty-six million, four hundred thirty-two thousand, four hundred twenty-one".