217728392525 has 24 divisors (see below), whose sum is σ = 308572137024. Its totient is φ = 149289840000.

The previous prime is 217728392509. The next prime is 217728392533. The reversal of 217728392525 is 525293827712.

It is a happy number.

It is not a de Polignac number, because 217728392525 - 2⁴ = 217728392509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3645554 + ... + 3704796.

It is an arithmetic number, because the mean of its divisors is an integer number (12857172376).

Almost surely, 2^217728392525 is an apocalyptic number.

217728392525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

217728392525 is a deficient number, since it is larger than the sum of its proper divisors (90843744499).

217728392525 is a wasteful number, since it uses less digits than its factorization.

217728392525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80261 (or 80256 counting only the distinct ones).

The product of its digits is 4233600, while the sum is 53.

The spelling of 217728392525 in words is "two hundred seventeen billion, seven hundred twenty-eight million, three hundred ninety-two thousand, five hundred twenty-five".