1561574649 has 4 divisors (see below), whose sum is σ = 2082099536. Its totient is φ = 1041049764.

The previous prime is 1561574647. The next prime is 1561574689. The reversal of 1561574649 is 9464751651.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9464751651 = 3 ⋅3154917217.

It is not a de Polignac number, because 1561574649 - 2¹ = 1561574647 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1561574598 and 1561574607.

It is not an unprimeable number, because it can be changed into a prime (1561574647) 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, 260262439 + ... + 260262444.

It is an arithmetic number, because the mean of its divisors is an integer number (520524884).

Almost surely, 2^1561574649 is an apocalyptic number.

It is an amenable number.

1561574649 is a deficient number, since it is larger than the sum of its proper divisors (520524887).

1561574649 is an equidigital number, since it uses as much as digits as its factorization.

1561574649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520524886.

The product of its digits is 907200, while the sum is 48.

The square root of 1561574649 is about 39516.7641514332. The cubic root of 1561574649 is about 1160.1680912280.

The spelling of 1561574649 in words is "one billion, five hundred sixty-one million, five hundred seventy-four thousand, six hundred forty-nine".