1421640 has 96 divisors (see below), whose sum is σ = 5054400. Its totient is φ = 343680.

The previous prime is 1421639. The next prime is 1421647. The reversal of 1421640 is 461241.

1421640 is a `hidden beast` number, since 1 + 4 + 21 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (1421647) 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, 3781 + ... + 4139.

It is an arithmetic number, because the mean of its divisors is an integer number (52650).

2^1421640 is an apocalyptic number.

1421640 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 1421640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2527200).

1421640 is an abundant number, since it is smaller than the sum of its proper divisors (3632760).

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

1421640 is a wasteful number, since it uses less digits than its factorization.

1421640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 380 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1421640 is about 1192.3254589247. The cubic root of 1421640 is about 112.4423408236.

Adding to 1421640 its reverse (461241), we get a palindrome (1882881).

The spelling of 1421640 in words is "one million, four hundred twenty-one thousand, six hundred forty".