1621440 has 84 divisors (see below), whose sum is σ = 5586984. Its totient is φ = 431616.

The previous prime is 1621439. The next prime is 1621457. The reversal of 1621440 is 441261.

1621440 is a `hidden beast` number, since 1 + 621 + 4 + 40 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2599 + ... + 3161.

2^1621440 is an apocalyptic number.

1621440 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 1621440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2793492).

1621440 is an abundant number, since it is smaller than the sum of its proper divisors (3965544).

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

1621440 is a wasteful number, since it uses less digits than its factorization.

1621440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 586 (or 573 counting only the distinct ones).

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

The square root of 1621440 is about 1273.3577659087. The cubic root of 1621440 is about 117.4808177529.

The spelling of 1621440 in words is "one million, six hundred twenty-one thousand, four hundred forty".