1661340 has 24 divisors (see below), whose sum is σ = 4651920. Its totient is φ = 443008.

The previous prime is 1661333. The next prime is 1661347. The reversal of 1661340 is 431661.

It is an interprime number because it is at equal distance from previous prime (1661333) and next prime (1661347).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661347) 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 in 7 ways as a sum of consecutive naturals, for example, 13785 + ... + 13904.

It is an arithmetic number, because the mean of its divisors is an integer number (193830).

2^1661340 is an apocalyptic number.

1661340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661340 is an abundant number, since it is smaller than the sum of its proper divisors (2990580).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1661340 is a wasteful number, since it uses less digits than its factorization.

1661340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27701 (or 27699 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 1661340 is about 1288.9297886231. The cubic root of 1661340 is about 118.4366661155.

It can be divided in two parts, 16613 and 40, that added together give a triangular number (16653 = T₁₈₂).

The spelling of 1661340 in words is "one million, six hundred sixty-one thousand, three hundred forty".