1661001611506 has 8 divisors (see below), whose sum is σ = 2492659647324. Its totient is φ = 830115062400.

The previous prime is 1661001611501. The next prime is 1661001611573. The reversal of 1661001611506 is 6051161001661.

It can be written as a sum of positive squares in 2 ways, for example, as 1651726188025 + 9275423481 = 1285195^2 + 96309^2 .

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

It is not an unprimeable number, because it can be changed into a prime (1661001611501) 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, 192866295 + ... + 192874906.

Almost surely, 2^{1661001611506} is an apocalyptic number.

1661001611506 is a deficient number, since it is larger than the sum of its proper divisors (831658035818).

1661001611506 is a wasteful number, since it uses less digits than its factorization.

1661001611506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 385743356.

The product of its (nonzero) digits is 6480, while the sum is 34.

The spelling of 1661001611506 in words is "one trillion, six hundred sixty-one billion, one million, six hundred eleven thousand, five hundred six".