1986421 has 2 divisors, whose sum is σ = 1986422. Its totient is φ = 1986420.

The previous prime is 1986401. The next prime is 1986437. The reversal of 1986421 is 1246891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1661521 + 324900 = 1289^2 + 570^2 .

It is an emirp because it is prime and its reverse (1246891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1986421 - 2⁷ = 1986293 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1986401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993210 + 993211.

It is an arithmetic number, because the mean of its divisors is an integer number (993211).

2^1986421 is an apocalyptic number.

It is an amenable number.

1986421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1986421 is an equidigital number, since it uses as much as digits as its factorization.

1986421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 31.

The square root of 1986421 is about 1409.4044841705. The cubic root of 1986421 is about 125.7063160901.

The spelling of 1986421 in words is "one million, nine hundred eighty-six thousand, four hundred twenty-one".