1890811649 has 2 divisors, whose sum is σ = 1890811650. Its totient is φ = 1890811648.

The previous prime is 1890811603. The next prime is 1890811651. The reversal of 1890811649 is 9461180981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1665211249 + 225600400 = 40807^2 + 15020^2 .

It is a cyclic number.

It is not a de Polignac number, because 1890811649 - 2²⁸ = 1622376193 is a prime.

Together with 1890811651, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1890816649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 945405824 + 945405825.

It is an arithmetic number, because the mean of its divisors is an integer number (945405825).

Almost surely, 2^1890811649 is an apocalyptic number.

It is an amenable number.

1890811649 is a deficient number, since it is larger than the sum of its proper divisors (1).

1890811649 is an equidigital number, since it uses as much as digits as its factorization.

1890811649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 47.

The square root of 1890811649 is about 43483.4640869377. The cubic root of 1890811649 is about 1236.5625507029.

The spelling of 1890811649 in words is "one billion, eight hundred ninety million, eight hundred eleven thousand, six hundred forty-nine".