1641640 has 128 divisors (see below), whose sum is σ = 5080320. Its totient is φ = 460800.

The previous prime is 1641637. The next prime is 1641641. The reversal of 1641640 is 461461.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (1641641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 40020 + ... + 40060.

It is an arithmetic number, because the mean of its divisors is an integer number (39690).

2^1641640 is an apocalyptic number.

1641640 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 1641640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2540160).

1641640 is an abundant number, since it is smaller than the sum of its proper divisors (3438680).

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

1641640 is a wasteful number, since it uses less digits than its factorization.

1641640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83 (or 79 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 1641640 is about 1281.2649999122. The cubic root of 1641640 is about 117.9666668272.

The spelling of 1641640 in words is "one million, six hundred forty-one thousand, six hundred forty".