1640420 has 12 divisors (see below), whose sum is σ = 3444924. Its totient is φ = 656160.

The previous prime is 1640399. The next prime is 1640423. The reversal of 1640420 is 240461.

It can be written as a sum of positive squares in 2 ways, for example, as 1240996 + 399424 = 1114^2 + 632^2 .

It is not an unprimeable number, because it can be changed into a prime (1640423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40991 + ... + 41030.

It is an arithmetic number, because the mean of its divisors is an integer number (287077).

2^1640420 is an apocalyptic number.

1640420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640420 is an abundant number, since it is smaller than the sum of its proper divisors (1804504).

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

1640420 is a wasteful number, since it uses less digits than its factorization.

1640420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82030 (or 82028 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 1640420 is about 1280.7888194390. The cubic root of 1640420 is about 117.9374369108.

Adding to 1640420 its reverse (240461), we get a palindrome (1880881).

The spelling of 1640420 in words is "one million, six hundred forty thousand, four hundred twenty".