1661451005 has 8 divisors (see below), whose sum is σ = 1993960152. Its totient is φ = 1329014848.

The previous prime is 1661450993. The next prime is 1661451007. The reversal of 1661451005 is 5001541661.

It can be written as a sum of positive squares in 4 ways, for example, as 158105476 + 1503345529 = 12574^2 + 38773^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1661451005 - 2⁶ = 1661450941 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 (1661451007) 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 7 ways as a sum of consecutive naturals, for example, 77879 + ... + 96891.

It is an arithmetic number, because the mean of its divisors is an integer number (249245019).

Almost surely, 2^1661451005 is an apocalyptic number.

It is an amenable number.

1661451005 is a deficient number, since it is larger than the sum of its proper divisors (332509147).

1661451005 is a wasteful number, since it uses less digits than its factorization.

1661451005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36495.

The product of its (nonzero) digits is 3600, while the sum is 29.

The square root of 1661451005 is about 40760.9004439303. The cubic root of 1661451005 is about 1184.3930389968.

Adding to 1661451005 its reverse (5001541661), we get a palindrome (6662992666).

The spelling of 1661451005 in words is "one billion, six hundred sixty-one million, four hundred fifty-one thousand, five".