1921491 has 24 divisors (see below), whose sum is σ = 3262896. Its totient is φ = 1074240.

The previous prime is 1921483. The next prime is 1921499. The reversal of 1921491 is 1941291.

It is an interprime number because it is at equal distance from previous prime (1921483) and next prime (1921499).

It is not a de Polignac number, because 1921491 - 2³ = 1921483 is a prime.

1921491 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1921499) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 541 + ... + 2033.

It is an arithmetic number, because the mean of its divisors is an integer number (135954).

2^1921491 is an apocalyptic number.

1921491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1921491 is a deficient number, since it is larger than the sum of its proper divisors (1341405).

1921491 is a wasteful number, since it uses less digits than its factorization.

1921491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1523 (or 1520 counting only the distinct ones).

The product of its digits is 648, while the sum is 27.

The square root of 1921491 is about 1386.1785599265. The cubic root of 1921491 is about 124.3214647169.

The spelling of 1921491 in words is "one million, nine hundred twenty-one thousand, four hundred ninety-one".