2104125661 has 4 divisors (see below), whose sum is σ = 2295409824. Its totient is φ = 1912841500.

The previous prime is 2104125631. The next prime is 2104125671. The reversal of 2104125661 is 1665214012.

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 2104125661 - 2¹¹ = 2104123613 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 (2104125601) 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 in 3 ways as a sum of consecutive naturals, for example, 95642065 + ... + 95642086.

It is an arithmetic number, because the mean of its divisors is an integer number (573852456).

Almost surely, 2^2104125661 is an apocalyptic number.

It is an amenable number.

2104125661 is a deficient number, since it is larger than the sum of its proper divisors (191284163).

2104125661 is a wasteful number, since it uses less digits than its factorization.

2104125661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191284162.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 2104125661 is about 45870.7495142602. The cubic root of 2104125661 is about 1281.4172252215.

Adding to 2104125661 its reverse (1665214012), we get a palindrome (3769339673).

It can be divided in two parts, 2104 and 125661, that added together give a triangular number (127765 = T₅₀₅).

The spelling of 2104125661 in words is "two billion, one hundred four million, one hundred twenty-five thousand, six hundred sixty-one".