1540231555 has 4 divisors (see below), whose sum is σ = 1848277872. Its totient is φ = 1232185240.

The previous prime is 1540231541. The next prime is 1540231571. The reversal of 1540231555 is 5551320451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5551320451 = 269 ⋅20636879.

It is not a de Polignac number, because 1540231555 - 2²⁹ = 1003360643 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 154023151 + ... + 154023160.

It is an arithmetic number, because the mean of its divisors is an integer number (462069468).

Almost surely, 2^1540231555 is an apocalyptic number.

1540231555 is a deficient number, since it is larger than the sum of its proper divisors (308046317).

1540231555 is an equidigital number, since it uses as much as digits as its factorization.

1540231555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 308046316.

The product of its (nonzero) digits is 15000, while the sum is 31.

The square root of 1540231555 is about 39245.7839136894. The cubic root of 1540231555 is about 1154.8582261344.

The spelling of 1540231555 in words is "one billion, five hundred forty million, two hundred thirty-one thousand, five hundred fifty-five".