199977121 has 4 divisors (see below), whose sum is σ = 201551872. Its totient is φ = 198402372.

The previous prime is 199977091. The next prime is 199977163. The reversal of 199977121 is 121779991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 121779991 = 6257 ⋅19463.

It is a cyclic number.

It is not a de Polignac number, because 199977121 - 2¹³ = 199968929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199972121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 787185 + ... + 787438.

It is an arithmetic number, because the mean of its divisors is an integer number (50387968).

Almost surely, 2^199977121 is an apocalyptic number.

It is an amenable number.

199977121 is a deficient number, since it is larger than the sum of its proper divisors (1574751).

199977121 is a wasteful number, since it uses less digits than its factorization.

199977121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1574750.

The product of its digits is 71442, while the sum is 46.

The square root of 199977121 is about 14141.3267057939. The cubic root of 199977121 is about 584.7812472583.

The spelling of 199977121 in words is "one hundred ninety-nine million, nine hundred seventy-seven thousand, one hundred twenty-one".