127992821 has 4 divisors (see below), whose sum is σ = 139628544. Its totient is φ = 116357100.

The previous prime is 127992817. The next prime is 127992833. The reversal of 127992821 is 128299721.

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: 128299721 = 11 ⋅11663611.

It is a cyclic number.

It is not a de Polignac number, because 127992821 - 2² = 127992817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (127991821) 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, 5817845 + ... + 5817866.

It is an arithmetic number, because the mean of its divisors is an integer number (34907136).

Almost surely, 2^127992821 is an apocalyptic number.

127992821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

127992821 is a deficient number, since it is larger than the sum of its proper divisors (11635723).

127992821 is a wasteful number, since it uses less digits than its factorization.

127992821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11635722.

The product of its digits is 36288, while the sum is 41.

The square root of 127992821 is about 11313.3912245622. The cubic root of 127992821 is about 503.9589979347.

The spelling of 127992821 in words is "one hundred twenty-seven million, nine hundred ninety-two thousand, eight hundred twenty-one".