1540897399 has 4 divisors (see below), whose sum is σ = 1541452680. Its totient is φ = 1540342120.

The previous prime is 1540897387. The next prime is 1540897403. The reversal of 1540897399 is 9937980451.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9937980451 = 7 ⋅1419711493.

It is a cyclic number.

It is not a de Polignac number, because 1540897399 - 2²¹ = 1538800247 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1540897199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 273457 + ... + 279034.

It is an arithmetic number, because the mean of its divisors is an integer number (385363170).

Almost surely, 2^1540897399 is an apocalyptic number.

1540897399 is a deficient number, since it is larger than the sum of its proper divisors (555281).

1540897399 is an equidigital number, since it uses as much as digits as its factorization.

1540897399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555280.

The product of its (nonzero) digits is 2449440, while the sum is 55.

The square root of 1540897399 is about 39254.2659974684. The cubic root of 1540897399 is about 1155.0246177046.

The spelling of 1540897399 in words is "one billion, five hundred forty million, eight hundred ninety-seven thousand, three hundred ninety-nine".