1631440 has 20 divisors (see below), whose sum is σ = 3793284. Its totient is φ = 652544.

The previous prime is 1631407. The next prime is 1631447. The reversal of 1631440 is 441361.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 732736 + 898704 = 856^2 + 948^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1631447) 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, 10117 + ... + 10276.

2^1631440 is an apocalyptic number.

1631440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1631440 is an abundant number, since it is smaller than the sum of its proper divisors (2161844).

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

1631440 is a wasteful number, since it uses less digits than its factorization.

1631440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20406 (or 20400 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 1631440 is about 1277.2783565065. The cubic root of 1631440 is about 117.7218383405.

The spelling of 1631440 in words is "one million, six hundred thirty-one thousand, four hundred forty".