501001116661 has 4 divisors (see below), whose sum is σ = 502771438912. Its totient is φ = 499230794412.

The previous prime is 501001116659. The next prime is 501001116697. The reversal of 501001116661 is 166611100105.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 501001116661 - 2¹ = 501001116659 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 (501001116631) 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, 885160701 + ... + 885161266.

It is an arithmetic number, because the mean of its divisors is an integer number (125692859728).

Almost surely, 2^501001116661 is an apocalyptic number.

It is an amenable number.

501001116661 is a deficient number, since it is larger than the sum of its proper divisors (1770322251).

501001116661 is a wasteful number, since it uses less digits than its factorization.

501001116661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1770322250.

The product of its (nonzero) digits is 1080, while the sum is 28.

Adding to 501001116661 its reverse (166611100105), we get a palindrome (667612216766).

The spelling of 501001116661 in words is "five hundred one billion, one million, one hundred sixteen thousand, six hundred sixty-one".