1987375561 has 8 divisors (see below), whose sum is σ = 2042817224. Its totient is φ = 1932024960.

The previous prime is 1987375517. The next prime is 1987375571. The reversal of 1987375561 is 1655737891.

It can be written as a sum of positive squares in 4 ways, for example, as 61921161 + 1925454400 = 7869^2 + 43880^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1987375561 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1987375499 and 1987375508.

It is not an unprimeable number, because it can be changed into a prime (1987375501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22741 + ... + 67021.

It is an arithmetic number, because the mean of its divisors is an integer number (255352153).

Almost surely, 2^1987375561 is an apocalyptic number.

It is an amenable number.

1987375561 is a deficient number, since it is larger than the sum of its proper divisors (55441663).

1987375561 is a wasteful number, since it uses less digits than its factorization.

1987375561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45531.

The product of its digits is 1587600, while the sum is 52.

The square root of 1987375561 is about 44579.9905899497. The cubic root of 1987375561 is about 1257.2644863521.

The spelling of 1987375561 in words is "one billion, nine hundred eighty-seven million, three hundred seventy-five thousand, five hundred sixty-one".