1904490661 has 2 divisors, whose sum is σ = 1904490662. Its totient is φ = 1904490660.

The previous prime is 1904490659. The next prime is 1904490701. The reversal of 1904490661 is 1660944091.

It is an a-pointer prime, because the next prime (1904490701) can be obtained adding 1904490661 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1737305761 + 167184900 = 41681^2 + 12930^2 .

It is a cyclic number.

It is not a de Polignac number, because 1904490661 - 2¹ = 1904490659 is a prime.

Together with 1904490659, 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 (1904490761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 952245330 + 952245331.

It is an arithmetic number, because the mean of its divisors is an integer number (952245331).

Almost surely, 2^1904490661 is an apocalyptic number.

It is an amenable number.

1904490661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1904490661 is an equidigital number, since it uses as much as digits as its factorization.

1904490661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 1904490661 is about 43640.4704488849. The cubic root of 1904490661 is about 1239.5373449606.

The spelling of 1904490661 in words is "one billion, nine hundred four million, four hundred ninety thousand, six hundred sixty-one".