1921587 has 4 divisors (see below), whose sum is σ = 2562120. Its totient is φ = 1281056.

The previous prime is 1921573. The next prime is 1921631. The reversal of 1921587 is 7851291.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1921587 - 2¹⁸ = 1659443 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (1921537) 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 in 3 ways as a sum of consecutive naturals, for example, 320262 + ... + 320267.

It is an arithmetic number, because the mean of its divisors is an integer number (640530).

2^1921587 is an apocalyptic number.

1921587 is a deficient number, since it is larger than the sum of its proper divisors (640533).

1921587 is an equidigital number, since it uses as much as digits as its factorization.

1921587 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640532.

The product of its digits is 5040, while the sum is 33.

The square root of 1921587 is about 1386.2131870676. The cubic root of 1921587 is about 124.3235350990.

It can be divided in two parts, 192 and 1587, that multiplied together give a square (304704 = 552²).

The spelling of 1921587 in words is "one million, nine hundred twenty-one thousand, five hundred eighty-seven".