1630891 has 2 divisors, whose sum is σ = 1630892. Its totient is φ = 1630890.

The previous prime is 1630859. The next prime is 1630897. The reversal of 1630891 is 1980361.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (1980361) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1630891 - 2⁵ = 1630859 is a prime.

It is not a weakly prime, because it can be changed into another prime (1630897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 815445 + 815446.

It is an arithmetic number, because the mean of its divisors is an integer number (815446).

2^1630891 is an apocalyptic number.

1630891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1630891 is an equidigital number, since it uses as much as digits as its factorization.

1630891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 1630891 is about 1277.0634283386. The cubic root of 1630891 is about 117.7086319012.

The spelling of 1630891 in words is "one million, six hundred thirty thousand, eight hundred ninety-one".