1566506551 has 4 divisors (see below), whose sum is σ = 1566930592. Its totient is φ = 1566082512.

The previous prime is 1566506527. The next prime is 1566506573. The reversal of 1566506551 is 1556056651.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1566506551 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 (1566506521) 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, 206430 + ... + 213883.

It is an arithmetic number, because the mean of its divisors is an integer number (391732648).

Almost surely, 2^1566506551 is an apocalyptic number.

1566506551 is a deficient number, since it is larger than the sum of its proper divisors (424041).

1566506551 is an equidigital number, since it uses as much as digits as its factorization.

1566506551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424040.

The product of its (nonzero) digits is 135000, while the sum is 40.

The square root of 1566506551 is about 39579.1176127008. The cubic root of 1566506551 is about 1161.3881891904.

The spelling of 1566506551 in words is "one billion, five hundred sixty-six million, five hundred six thousand, five hundred fifty-one".