1921390 has 16 divisors (see below), whose sum is σ = 3476160. Its totient is φ = 764640.

The previous prime is 1921363. The next prime is 1921393. The reversal of 1921390 is 931291.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921393) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2356 + ... + 3064.

It is an arithmetic number, because the mean of its divisors is an integer number (217260).

2^1921390 is an apocalyptic number.

1921390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1921390 is a deficient number, since it is larger than the sum of its proper divisors (1554770).

1921390 is a wasteful number, since it uses less digits than its factorization.

1921390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 987.

The product of its (nonzero) digits is 486, while the sum is 25.

The square root of 1921390 is about 1386.1421283548. The cubic root of 1921390 is about 124.3192864280.

Subtracting from 1921390 its reverse (931291), we obtain a palindrome (990099).

The spelling of 1921390 in words is "one million, nine hundred twenty-one thousand, three hundred ninety".