1540921 has 4 divisors (see below), whose sum is σ = 1566244. Its totient is φ = 1515600.

The previous prime is 1540901. The next prime is 1540927. The reversal of 1540921 is 1290451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1290451 = 109 ⋅11839.

It can be written as a sum of positive squares in 2 ways, for example, as 112896 + 1428025 = 336^2 + 1195^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1540921 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1540892 and 1540901.

It is not an unprimeable number, because it can be changed into a prime (1540927) 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, 12570 + ... + 12691.

It is an arithmetic number, because the mean of its divisors is an integer number (391561).

2^1540921 is an apocalyptic number.

It is an amenable number.

1540921 is a deficient number, since it is larger than the sum of its proper divisors (25323).

1540921 is an equidigital number, since it uses as much as digits as its factorization.

1540921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25322.

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 1540921 is about 1241.3383906091. The cubic root of 1540921 is about 115.5030514614.

The spelling of 1540921 in words is "one million, five hundred forty thousand, nine hundred twenty-one".