1987465561 has 9 divisors (see below), whose sum is σ = 2010782781. Its totient is φ = 1964417184.

The previous prime is 1987465541. The next prime is 1987465573. The reversal of 1987465561 is 1655647891.

The square root of 1987465561 is 44581.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 805481161 + 1181984400 = 28381^2 + 34380^2 .

It is not a de Polignac number, because 1987465561 - 2⁹ = 1987465049 is a prime.

It is a super-2 number, since 2×1987465561² = 7900038712322089442, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1987465499 and 1987465508.

It is not an unprimeable number, because it can be changed into a prime (1987465541) 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 8 ways as a sum of consecutive naturals, for example, 4859125 + ... + 4859533.

It is an arithmetic number, because the mean of its divisors is an integer number (223420309).

Almost surely, 2^1987465561 is an apocalyptic number.

1987465561 is the 44581-st square number.

1987465561 is the 22291-st centered octagonal number.

It is an amenable number.

1987465561 is a deficient number, since it is larger than the sum of its proper divisors (23317220).

1987465561 is an frugal number, since it uses more digits than its factorization.

1987465561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1036 (or 518 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 52.

The cubic root of 1987465561 is about 1257.2834648311.

The spelling of 1987465561 in words is "one billion, nine hundred eighty-seven million, four hundred sixty-five thousand, five hundred sixty-one".