1870991 has 2 divisors, whose sum is σ = 1870992. Its totient is φ = 1870990.

The previous prime is 1870961. The next prime is 1871017. The reversal of 1870991 is 1990781.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1870991 - 2⁶ = 1870927 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1870951) 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, 935495 + 935496.

It is an arithmetic number, because the mean of its divisors is an integer number (935496).

2^1870991 is an apocalyptic number.

1870991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1870991 is an equidigital number, since it uses as much as digits as its factorization.

1870991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 35.

The square root of 1870991 is about 1367.8417306107. The cubic root of 1870991 is about 123.2226561681. Note that the first 3 decimals are identical.

The spelling of 1870991 in words is "one million, eight hundred seventy thousand, nine hundred ninety-one".