1561648945 has 8 divisors (see below), whose sum is σ = 1874307240. Its totient is φ = 1249100160.

The previous prime is 1561648939. The next prime is 1561648967. The reversal of 1561648945 is 5498461651.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 134689 + 1561514256 = 367^2 + 39516^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1561648945 - 2³ = 1561648937 is a prime.

It is a super-2 number, since 2×1561648945² = 4877494854839226050, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8205 + ... + 56485.

It is an arithmetic number, because the mean of its divisors is an integer number (234288405).

Almost surely, 2^1561648945 is an apocalyptic number.

It is an amenable number.

1561648945 is a deficient number, since it is larger than the sum of its proper divisors (312658295).

1561648945 is an equidigital number, since it uses as much as digits as its factorization.

1561648945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54755.

The product of its digits is 1036800, while the sum is 49.

The square root of 1561648945 is about 39517.7041969799. The cubic root of 1561648945 is about 1160.1864902804.

The spelling of 1561648945 in words is "one billion, five hundred sixty-one million, six hundred forty-eight thousand, nine hundred forty-five".