1661533567 has 4 divisors (see below), whose sum is σ = 1715131456. Its totient is φ = 1607935680.

The previous prime is 1661533561. The next prime is 1661533649. The reversal of 1661533567 is 7653351661.

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

It is a cyclic number.

It is not a de Polignac number, because 1661533567 - 2⁷ = 1661533439 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 (1661533561) 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, 26798898 + ... + 26798959.

It is an arithmetic number, because the mean of its divisors is an integer number (428782864).

Almost surely, 2^1661533567 is an apocalyptic number.

1661533567 is a deficient number, since it is larger than the sum of its proper divisors (53597889).

1661533567 is an equidigital number, since it uses as much as digits as its factorization.

1661533567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53597888.

The product of its digits is 340200, while the sum is 43.

The square root of 1661533567 is about 40761.9131911151. The cubic root of 1661533567 is about 1184.4126572377.

The spelling of 1661533567 in words is "one billion, six hundred sixty-one million, five hundred thirty-three thousand, five hundred sixty-seven".