197239905 has 12 divisors (see below), whose sum is σ = 341882580. Its totient is φ = 105194592.

The previous prime is 197239877. The next prime is 197239907. The reversal of 197239905 is 509932791.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 136960209 + 60279696 = 11703^2 + 7764^2 .

It is not a de Polignac number, because 197239905 - 2¹⁸ = 196977761 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 4383109 = 197239905 / (1 + 9 + 7 + 2 + 3 + 9 + 9 + 0 + 5).

It is not an unprimeable number, because it can be changed into a prime (197239907) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2191510 + ... + 2191599.

It is an arithmetic number, because the mean of its divisors is an integer number (28490215).

Almost surely, 2^197239905 is an apocalyptic number.

197239905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

197239905 is a deficient number, since it is larger than the sum of its proper divisors (144642675).

197239905 is a wasteful number, since it uses less digits than its factorization.

197239905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4383120 (or 4383117 counting only the distinct ones).

The product of its (nonzero) digits is 153090, while the sum is 45.

The square root of 197239905 is about 14044.2125090729. The cubic root of 197239905 is about 582.1008876722.

The spelling of 197239905 in words is "one hundred ninety-seven million, two hundred thirty-nine thousand, nine hundred five".