199891385507025 has 81 divisors (see below), whose sum is σ = 361576938335067. Its totient is φ = 105562165788000.

The previous prime is 199891385507003. The next prime is 199891385507041. The reversal of 199891385507025 is 520705583198991.

The square root of 199891385507025 is 14138295.

It is a perfect power (a square), and thus also a powerful number.

199891385507025 is a `hidden beast` number, since 1 + 9 + 9 + 8 + 9 + 13 + 85 + 507 + 0 + 25 = 666.

It can be written as a sum of positive squares in only one way, i.e., 71960898782529 + 127930486724496 = 8482977^2 + 11310636^2 .

It is not a de Polignac number, because 199891385507025 - 2¹⁷ = 199891385375953 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 21843661200 + ... + 21843670350.

Almost surely, 2^{199891385507025} is an apocalyptic number.

199891385507025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

199891385507025 is the 14138295-th square number.

199891385507025 is the 7069148-th centered octagonal number.

It is an amenable number.

199891385507025 is a deficient number, since it is larger than the sum of its proper divisors (161685552828042).

199891385507025 is an frugal number, since it uses more digits than its factorization.

199891385507025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18524 (or 9262 counting only the distinct ones).

The product of its (nonzero) digits is 244944000, while the sum is 72.

The spelling of 199891385507025 in words is "one hundred ninety-nine trillion, eight hundred ninety-one billion, three hundred eighty-five million, five hundred seven thousand, twenty-five".