1561572667 has 4 divisors (see below), whose sum is σ = 1561663440. Its totient is φ = 1561481896.

The previous prime is 1561572653. The next prime is 1561572709. The reversal of 1561572667 is 7662751651.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561572667 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561572167) 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, 10792 + ... + 56917.

It is an arithmetic number, because the mean of its divisors is an integer number (390415860).

Almost surely, 2^1561572667 is an apocalyptic number.

1561572667 is a deficient number, since it is larger than the sum of its proper divisors (90773).

1561572667 is an equidigital number, since it uses as much as digits as its factorization.

1561572667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90772.

The product of its digits is 529200, while the sum is 46.

The square root of 1561572667 is about 39516.7390734610. The cubic root of 1561572667 is about 1160.1676003871.

The spelling of 1561572667 in words is "one billion, five hundred sixty-one million, five hundred seventy-two thousand, six hundred sixty-seven".