1980405 has 24 divisors (see below), whose sum is σ = 3923712. Its totient is φ = 905184.

The previous prime is 1980401. The next prime is 1980409. The reversal of 1980405 is 5040891.

It is an interprime number because it is at equal distance from previous prime (1980401) and next prime (1980409).

It is not a de Polignac number, because 1980405 - 2² = 1980401 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1980401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2829 + ... + 3458.

It is an arithmetic number, because the mean of its divisors is an integer number (163488).

2^1980405 is an apocalyptic number.

1980405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1980405 is a deficient number, since it is larger than the sum of its proper divisors (1943307).

1980405 is a wasteful number, since it uses less digits than its factorization.

1980405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6305 (or 6302 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 1980405 is about 1407.2686310723. The cubic root of 1980405 is about 125.5792846210.

The spelling of 1980405 in words is "one million, nine hundred eighty thousand, four hundred five".