1405640 has 16 divisors (see below), whose sum is σ = 3162780. Its totient is φ = 562240.

The previous prime is 1405637. The next prime is 1405643. The reversal of 1405640 is 465041.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1405637) and next prime (1405643).

It can be written as a sum of positive squares in 2 ways, for example, as 1387684 + 17956 = 1178^2 + 134^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (1405643) 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, 17531 + ... + 17610.

2^1405640 is an apocalyptic number.

1405640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1405640 is an abundant number, since it is smaller than the sum of its proper divisors (1757140).

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

1405640 is a wasteful number, since it uses less digits than its factorization.

1405640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35152 (or 35148 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 1405640 is about 1185.5968960823. The cubic root of 1405640 is about 112.0189168728.

The spelling of 1405640 in words is "one million, four hundred five thousand, six hundred forty".