1649680 has 40 divisors (see below), whose sum is σ = 4064472. Its totient is φ = 620544.

The previous prime is 1649677. The next prime is 1649689. The reversal of 1649680 is 869461.

It can be written as a sum of positive squares in 4 ways, for example, as 51984 + 1597696 = 228^2 + 1264^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1649689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 754 + ... + 1966.

2^1649680 is an apocalyptic number.

1649680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1649680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2032236).

1649680 is an abundant number, since it is smaller than the sum of its proper divisors (2414792).

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

1649680 is a wasteful number, since it uses less digits than its factorization.

1649680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1243 (or 1237 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 1649680 is about 1284.3986919956. The cubic root of 1649680 is about 118.1589355015.

The spelling of 1649680 in words is "one million, six hundred forty-nine thousand, six hundred eighty".