1987961 has 4 divisors (see below), whose sum is σ = 1990800. Its totient is φ = 1985124.

The previous prime is 1987939. The next prime is 1987969. The reversal of 1987961 is 1697891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 1987961 - 2¹⁴ = 1971577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1987969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 470 + ... + 2048.

It is an arithmetic number, because the mean of its divisors is an integer number (497700).

2^1987961 is an apocalyptic number.

It is an amenable number.

1987961 is a deficient number, since it is larger than the sum of its proper divisors (2839).

1987961 is a wasteful number, since it uses less digits than its factorization.

1987961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2838.

The product of its digits is 27216, while the sum is 41.

The square root of 1987961 is about 1409.9507083583. The cubic root of 1987961 is about 125.7387928781.

The spelling of 1987961 in words is "one million, nine hundred eighty-seven thousand, nine hundred sixty-one".