1689435540 has 432 divisors, whose sum is σ = 6075014400. Its totient is φ = 378473472.

The previous prime is 1689435533. The next prime is 1689435547. The reversal of 1689435540 is 455349861.

1689435540 is a `hidden beast` number, since 1 + 6 + 8 + 94 + 3 + 554 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (1689435533) and next prime (1689435547).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1689435547) by changing a digit.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 21385221 + ... + 21385299.

Almost surely, 2^1689435540 is an apocalyptic number.

1689435540 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 1689435540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3037507200).

1689435540 is an abundant number, since it is smaller than the sum of its proper divisors (4385578860).

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

1689435540 is a wasteful number, since it uses less digits than its factorization.

1689435540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176 (or 158 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The square root of 1689435540 is about 41102.7437040400. The cubic root of 1689435540 is about 1191.0057970181.

The spelling of 1689435540 in words is "one billion, six hundred eighty-nine million, four hundred thirty-five thousand, five hundred forty".