197891555 has 16 divisors (see below), whose sum is σ = 253497600. Its totient is φ = 147863520.

The previous prime is 197891537. The next prime is 197891557. The reversal of 197891555 is 555198791.

It is not a de Polignac number, because 197891555 - 2¹⁰ = 197890531 is a prime.

It is a super-2 number, since 2×197891555² = 78322135080636050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (197891557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7925 + ... + 21414.

It is an arithmetic number, because the mean of its divisors is an integer number (15843600).

Almost surely, 2^197891555 is an apocalyptic number.

197891555 is a deficient number, since it is larger than the sum of its proper divisors (55606045).

197891555 is a wasteful number, since it uses less digits than its factorization.

197891555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29434.

The product of its digits is 567000, while the sum is 50.

The square root of 197891555 is about 14067.3933264127. The cubic root of 197891555 is about 582.7412399440.

The spelling of 197891555 in words is "one hundred ninety-seven million, eight hundred ninety-one thousand, five hundred fifty-five".