1540405649 has 4 divisors (see below), whose sum is σ = 1631017764. Its totient is φ = 1449793536.

The previous prime is 1540405619. The next prime is 1540405661. The reversal of 1540405649 is 9465040451.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 538240000 + 1002165649 = 23200^2 + 31657^2 .

It is a cyclic number.

It is not a de Polignac number, because 1540405649 - 2⁸ = 1540405393 is a prime.

It is a super-2 number, since 2×1540405649² = 4745699126942222402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1540405619) 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, 45306032 + ... + 45306065.

It is an arithmetic number, because the mean of its divisors is an integer number (407754441).

Almost surely, 2^1540405649 is an apocalyptic number.

It is an amenable number.

1540405649 is a deficient number, since it is larger than the sum of its proper divisors (90612115).

1540405649 is an equidigital number, since it uses as much as digits as its factorization.

1540405649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90612114.

The product of its (nonzero) digits is 86400, while the sum is 38.

The square root of 1540405649 is about 39248.0018472278. The cubic root of 1540405649 is about 1154.9017361103.

The spelling of 1540405649 in words is "one billion, five hundred forty million, four hundred five thousand, six hundred forty-nine".