127921993 has 4 divisors (see below), whose sum is σ = 128129940. Its totient is φ = 127714048.

The previous prime is 127921979. The next prime is 127922017. The reversal of 127921993 is 399129721.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 59413264 + 68508729 = 7708^2 + 8277^2 .

It is a cyclic number.

It is not a de Polignac number, because 127921993 - 2¹³ = 127913801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (127921933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103048 + ... + 104281.

It is an arithmetic number, because the mean of its divisors is an integer number (32032485).

Almost surely, 2^127921993 is an apocalyptic number.

It is an amenable number.

127921993 is a deficient number, since it is larger than the sum of its proper divisors (207947).

127921993 is an equidigital number, since it uses as much as digits as its factorization.

127921993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207946.

The product of its digits is 61236, while the sum is 43.

The square root of 127921993 is about 11310.2605186618. The cubic root of 127921993 is about 503.8660213813.

The spelling of 127921993 in words is "one hundred twenty-seven million, nine hundred twenty-one thousand, nine hundred ninety-three".