2021515536661 has 8 divisors (see below), whose sum is σ = 2024026383960. Its totient is φ = 2019006087168.

The previous prime is 2021515536653. The next prime is 2021515536679. The reversal of 2021515536661 is 1666355151202.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 7724652100 + 2013790884561 = 87890^2 + 1419081^2 .

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 2021515536661 - 2³ = 2021515536653 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 (2021515536641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2559765 + ... + 3255061.

It is an arithmetic number, because the mean of its divisors is an integer number (253003297995).

Almost surely, 2^{2021515536661} is an apocalyptic number.

It is an amenable number.

2021515536661 is a deficient number, since it is larger than the sum of its proper divisors (2510847299).

2021515536661 is a wasteful number, since it uses less digits than its factorization.

2021515536661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 698903.

The product of its (nonzero) digits is 324000, while the sum is 43.

The spelling of 2021515536661 in words is "two trillion, twenty-one billion, five hundred fifteen million, five hundred thirty-six thousand, six hundred sixty-one".