1540721 has 8 divisors (see below), whose sum is σ = 1896384. Its totient is φ = 1218960.

The previous prime is 1540711. The next prime is 1540751. The reversal of 1540721 is 1270451.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1540721 - 2¹⁴ = 1524337 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1540693 and 1540702.

It is not an unprimeable number, because it can be changed into a prime (1540711) 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, 8375 + ... + 8556.

It is an arithmetic number, because the mean of its divisors is an integer number (237048).

2^1540721 is an apocalyptic number.

It is an amenable number.

1540721 is a deficient number, since it is larger than the sum of its proper divisors (355663).

1540721 is a wasteful number, since it uses less digits than its factorization.

1540721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16951.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 1540721 is about 1241.2578297840. The cubic root of 1540721 is about 115.4980541016.

The spelling of 1540721 in words is "one million, five hundred forty thousand, seven hundred twenty-one".