1691252640 has 432 divisors, whose sum is σ = 7327363680. Its totient is φ = 351267840.

The previous prime is 1691252627. The next prime is 1691252663. The reversal of 1691252640 is 462521961.

1691252640 is a `hidden beast` number, since 1 + 6 + 9 + 1 + 2 + 5 + 2 + 640 = 666.

1691252640 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1691252595 and 1691252604.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 775071 + ... + 777249.

It is an arithmetic number, because the mean of its divisors is an integer number (16961490).

Almost surely, 2^1691252640 is an apocalyptic number.

1691252640 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 1691252640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3663681840).

1691252640 is an abundant number, since it is smaller than the sum of its proper divisors (5636111040).

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

1691252640 is a wasteful number, since it uses less digits than its factorization.

1691252640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2225 (or 2207 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 1691252640 is about 41124.8421273565. The cubic root of 1691252640 is about 1191.4326459351.

The spelling of 1691252640 in words is "one billion, six hundred ninety-one million, two hundred fifty-two thousand, six hundred forty".