5015000121661 has 4 divisors (see below), whose sum is σ = 5015009266812. Its totient is φ = 5014990976512.

The previous prime is 5015000121647. The next prime is 5015000121667. The reversal of 5015000121661 is 1661210005105.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 1946599782436 + 3068400339225 = 1395206^2 + 1751685^2 .

It is a cyclic number.

It is not a de Polignac number, because 5015000121661 - 2³⁷ = 4877561168189 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 (5015000121667) 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, 3693700 + ... + 4865533.

It is an arithmetic number, because the mean of its divisors is an integer number (1253752316703).

Almost surely, 2^{5015000121661} is an apocalyptic number.

It is an amenable number.

5015000121661 is a deficient number, since it is larger than the sum of its proper divisors (9145151).

5015000121661 is an equidigital number, since it uses as much as digits as its factorization.

5015000121661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9145150.

The product of its (nonzero) digits is 1800, while the sum is 28.

Adding to 5015000121661 its reverse (1661210005105), we get a palindrome (6676210126766).

The spelling of 5015000121661 in words is "five trillion, fifteen billion, one hundred twenty-one thousand, six hundred sixty-one".