1645740 has 72 divisors (see below), whose sum is σ = 5136768. Its totient is φ = 426240.

The previous prime is 1645733. The next prime is 1645747. The reversal of 1645740 is 475461.

1645740 = 180² + 181² + ... + 220².

It is an interprime number because it is at equal distance from previous prime (1645733) and next prime (1645747).

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (1645747) 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, 7269 + ... + 7491.

It is an arithmetic number, because the mean of its divisors is an integer number (71344).

2^1645740 is an apocalyptic number.

1645740 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 1645740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2568384).

1645740 is an abundant number, since it is smaller than the sum of its proper divisors (3491028).

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

1645740 is a wasteful number, since it uses less digits than its factorization.

1645740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279 (or 274 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 1645740 is about 1282.8639834371. The cubic root of 1645740 is about 118.0647925311.

The spelling of 1645740 in words is "one million, six hundred forty-five thousand, seven hundred forty".