1987939 has 2 divisors, whose sum is σ = 1987940. Its totient is φ = 1987938.

The previous prime is 1987919. The next prime is 1987969. The reversal of 1987939 is 9397891.

It is a weak prime.

It is an emirp because it is prime and its reverse (9397891) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1987939 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1987919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993969 + 993970.

It is an arithmetic number, because the mean of its divisors is an integer number (993970).

2^1987939 is an apocalyptic number.

1987939 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987939 is an equidigital number, since it uses as much as digits as its factorization.

1987939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 46.

The square root of 1987939 is about 1409.9429066455. The cubic root of 1987939 is about 125.7383290421.

It can be divided in two parts, 1987 and 939, that added together give a triangular number (2926 = T₇₆).

The spelling of 1987939 in words is "one million, nine hundred eighty-seven thousand, nine hundred thirty-nine".