1691255323920 has 160 divisors (see below), whose sum is σ = 5318667512064. Its totient is φ = 444487680000.

The previous prime is 1691255323889. The next prime is 1691255323921. The reversal of 1691255323920 is 293235521961.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 1691255323920.

It is not an unprimeable number, because it can be changed into a prime (1691255323921) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 51120504 + ... + 51153576.

Almost surely, 2^{1691255323920} is an apocalyptic number.

1691255323920 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 1691255323920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2659333756032).

1691255323920 is an abundant number, since it is smaller than the sum of its proper divisors (3627412188144).

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

1691255323920 is a wasteful number, since it uses less digits than its factorization.

1691255323920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36161 (or 36155 counting only the distinct ones).

The product of its (nonzero) digits is 874800, while the sum is 48.

The spelling of 1691255323920 in words is "one trillion, six hundred ninety-one billion, two hundred fifty-five million, three hundred twenty-three thousand, nine hundred twenty".