17991697255420 has 96 divisors (see below), whose sum is σ = 44587025473536. Its totient is φ = 5967714182400.

The previous prime is 17991697255379. The next prime is 17991697255429. The reversal of 17991697255420 is 2455279619971.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (17991697255429) 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, 13153929 + ... + 14457151.

It is an arithmetic number, because the mean of its divisors is an integer number (464448182016).

Almost surely, 2^{17991697255420} is an apocalyptic number.

17991697255420 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 17991697255420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22293512736768).

17991697255420 is an abundant number, since it is smaller than the sum of its proper divisors (26595328218116).

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

17991697255420 is a wasteful number, since it uses less digits than its factorization.

17991697255420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306451 (or 1306449 counting only the distinct ones).

The product of its (nonzero) digits is 85730400, while the sum is 67.

The spelling of 17991697255420 in words is "seventeen trillion, nine hundred ninety-one billion, six hundred ninety-seven million, two hundred fifty-five thousand, four hundred twenty".