1987157 has 2 divisors, whose sum is σ = 1987158. Its totient is φ = 1987156.

The previous prime is 1987151. The next prime is 1987189. The reversal of 1987157 is 7517891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1196836 + 790321 = 1094^2 + 889^2 .

It is a cyclic number.

It is not a de Polignac number, because 1987157 - 2¹⁰ = 1986133 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1987157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1987151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993578 + 993579.

It is an arithmetic number, because the mean of its divisors is an integer number (993579).

2^1987157 is an apocalyptic number.

It is an amenable number.

1987157 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987157 is an equidigital number, since it uses as much as digits as its factorization.

1987157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17640, while the sum is 38.

The square root of 1987157 is about 1409.6655631745. The cubic root of 1987157 is about 125.7218395574.

It can be divided in two parts, 198 and 7157, that multiplied together give a triangular number (1417086 = T₁₆₈₃).

The spelling of 1987157 in words is "one million, nine hundred eighty-seven thousand, one hundred fifty-seven".