1661206506 has 8 divisors (see below), whose sum is σ = 3322413024. Its totient is φ = 553735500.

The previous prime is 1661206453. The next prime is 1661206531. The reversal of 1661206506 is 6056021661.

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

1661206506 is an admirable number.

It is an unprimeable number.

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, 138433870 + ... + 138433881.

It is an arithmetic number, because the mean of its divisors is an integer number (415301628).

Almost surely, 2^1661206506 is an apocalyptic number.

1661206506 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1661206506 is a wasteful number, since it uses less digits than its factorization.

1661206506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276867756.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 1661206506 is about 40757.9011481210. The cubic root of 1661206506 is about 1184.3349377509.

The spelling of 1661206506 in words is "one billion, six hundred sixty-one million, two hundred six thousand, five hundred six".