1987421 has 4 divisors (see below), whose sum is σ = 2017152. Its totient is φ = 1957692.

The previous prime is 1987411. The next prime is 1987429. The reversal of 1987421 is 1247891.

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 an emirpimes, since its reverse is a distinct semiprime: 1247891 = 269 ⋅4639.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1987421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987429) 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, 14765 + ... + 14898.

It is an arithmetic number, because the mean of its divisors is an integer number (504288).

2^1987421 is an apocalyptic number.

It is an amenable number.

1987421 is a deficient number, since it is larger than the sum of its proper divisors (29731).

1987421 is an equidigital number, since it uses as much as digits as its factorization.

1987421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29730.

The product of its digits is 4032, while the sum is 32.

The square root of 1987421 is about 1409.7591992961. The cubic root of 1987421 is about 125.7274068236.

The spelling of 1987421 in words is "one million, nine hundred eighty-seven thousand, four hundred twenty-one".