1987090961 has 2 divisors, whose sum is σ = 1987090962. Its totient is φ = 1987090960.

The previous prime is 1987090909. The next prime is 1987090997. The reversal of 1987090961 is 1690907891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1921156561 + 65934400 = 43831^2 + 8120^2 .

It is an emirp because it is prime and its reverse (1690907891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1987090961 - 2¹⁸ = 1986828817 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1987093961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993545480 + 993545481.

It is an arithmetic number, because the mean of its divisors is an integer number (993545481).

Almost surely, 2^1987090961 is an apocalyptic number.

It is an amenable number.

1987090961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987090961 is an equidigital number, since it uses as much as digits as its factorization.

1987090961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 244944, while the sum is 50.

The square root of 1987090961 is about 44576.7984606342. The cubic root of 1987090961 is about 1257.2044684133.

The spelling of 1987090961 in words is "one billion, nine hundred eighty-seven million, ninety thousand, nine hundred sixty-one".