2102520661 has 2 divisors, whose sum is σ = 2102520662. Its totient is φ = 2102520660.

The previous prime is 2102520659. The next prime is 2102520697. The reversal of 2102520661 is 1660252012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1645843761 + 456676900 = 40569^2 + 21370^2 .

It is a cyclic number.

It is not a de Polignac number, because 2102520661 - 2¹ = 2102520659 is a prime.

Together with 2102520659, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2102521661) by changing a digit.

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 as a sum of consecutive naturals, namely, 1051260330 + 1051260331.

It is an arithmetic number, because the mean of its divisors is an integer number (1051260331).

Almost surely, 2^2102520661 is an apocalyptic number.

It is an amenable number.

2102520661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2102520661 is an equidigital number, since it uses as much as digits as its factorization.

2102520661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 2102520661 is about 45853.2513678147. The cubic root of 2102520661 is about 1281.0913261491.

Adding to 2102520661 its reverse (1660252012), we get a palindrome (3762772673).

The spelling of 2102520661 in words is "two billion, one hundred two million, five hundred twenty thousand, six hundred sixty-one".