1561965087 has 4 divisors (see below), whose sum is σ = 2082620120. Its totient is φ = 1041310056.

The previous prime is 1561965077. The next prime is 1561965089. The reversal of 1561965087 is 7805691651.

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

It is not a de Polignac number, because 1561965087 - 2²² = 1557770783 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 (1561965089) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 260327512 + ... + 260327517.

It is an arithmetic number, because the mean of its divisors is an integer number (520655030).

Almost surely, 2^1561965087 is an apocalyptic number.

1561965087 is a deficient number, since it is larger than the sum of its proper divisors (520655033).

1561965087 is an equidigital number, since it uses as much as digits as its factorization.

1561965087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 520655032.

The product of its (nonzero) digits is 453600, while the sum is 48.

The square root of 1561965087 is about 39521.7039991952. The cubic root of 1561965087 is about 1160.2647748250.

The spelling of 1561965087 in words is "one billion, five hundred sixty-one million, nine hundred sixty-five thousand, eighty-seven".