1987551 has 8 divisors (see below), whose sum is σ = 2944560. Its totient is φ = 1325016.

The previous prime is 1987549. The next prime is 1987577. The reversal of 1987551 is 1557891.

It is not a de Polignac number, because 1987551 - 2¹ = 1987549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987501) 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, 36780 + ... + 36833.

It is an arithmetic number, because the mean of its divisors is an integer number (368070).

2^1987551 is an apocalyptic number.

1987551 is a deficient number, since it is larger than the sum of its proper divisors (957009).

1987551 is an equidigital number, since it uses as much as digits as its factorization.

1987551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73622 (or 73616 counting only the distinct ones).

The product of its digits is 12600, while the sum is 36.

The square root of 1987551 is about 1409.8053057071. The cubic root of 1987551 is about 125.7301480993.

The spelling of 1987551 in words is "one million, nine hundred eighty-seven thousand, five hundred fifty-one".