1540245521 has 4 divisors (see below), whose sum is σ = 1540363812. Its totient is φ = 1540127232.

The previous prime is 1540245493. The next prime is 1540245557. The reversal of 1540245521 is 1255420451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1255420451 = 41 ⋅30620011.

It can be written as a sum of positive squares in 2 ways, for example, as 1060153600 + 480091921 = 32560^2 + 21911^2 .

It is a cyclic number.

It is not a de Polignac number, because 1540245521 - 2¹⁴ = 1540229137 is a prime.

It is a super-3 number, since 3×1540245521³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1540245121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36800 + ... + 66593.

It is an arithmetic number, because the mean of its divisors is an integer number (385090953).

Almost surely, 2^1540245521 is an apocalyptic number.

It is an amenable number.

1540245521 is a deficient number, since it is larger than the sum of its proper divisors (118291).

1540245521 is a wasteful number, since it uses less digits than its factorization.

1540245521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 118290.

The product of its (nonzero) digits is 8000, while the sum is 29.

The square root of 1540245521 is about 39245.9618432266. The cubic root of 1540245521 is about 1154.8617166705.

Adding to 1540245521 its reverse (1255420451), we get a palindrome (2795665972).

The spelling of 1540245521 in words is "one billion, five hundred forty million, two hundred forty-five thousand, five hundred twenty-one".