1618640 has 20 divisors (see below), whose sum is σ = 3763524. Its totient is φ = 647424.

The previous prime is 1618637. The next prime is 1618663. The reversal of 1618640 is 468161.

It can be written as a sum of positive squares in 2 ways, for example, as 712336 + 906304 = 844^2 + 952^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a plaindrome in base 13.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10037 + ... + 10196.

2^1618640 is an apocalyptic number.

1618640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1618640 is an abundant number, since it is smaller than the sum of its proper divisors (2144884).

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

1618640 is a wasteful number, since it uses less digits than its factorization.

1618640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20246 (or 20240 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 1618640 is about 1272.2578355035. The cubic root of 1618640 is about 117.4131544783.

The spelling of 1618640 in words is "one million, six hundred eighteen thousand, six hundred forty".