127989981 has 12 divisors (see below), whose sum is σ = 211285152. Its totient is φ = 73137096.

The previous prime is 127989971. The next prime is 127989989. The reversal of 127989981 is 189989721.

It is not a de Polignac number, because 127989981 - 2⁷ = 127989853 is a prime.

It is a super-2 number, since 2×127989981² = 32762870472760722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (127989989) 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, 1015731 + ... + 1015856.

It is an arithmetic number, because the mean of its divisors is an integer number (17607096).

Almost surely, 2^127989981 is an apocalyptic number.

It is an amenable number.

127989981 is a deficient number, since it is larger than the sum of its proper divisors (83295171).

127989981 is a wasteful number, since it uses less digits than its factorization.

127989981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2031600 (or 2031597 counting only the distinct ones).

The product of its digits is 653184, while the sum is 54.

The square root of 127989981 is about 11313.2657088924. The cubic root of 127989981 is about 503.9552705013.

The spelling of 127989981 in words is "one hundred twenty-seven million, nine hundred eighty-nine thousand, nine hundred eighty-one".