127980000781 has 4 divisors (see below), whose sum is σ = 127984364064. Its totient is φ = 127975637500.

The previous prime is 127980000779. The next prime is 127980000809. The reversal of 127980000781 is 187000089721.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 127980000781 - 2¹ = 127980000779 is a prime.

It is a super-2 number, since 2×127980000781² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (127980000721) 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, 2137345 + ... + 2196406.

It is an arithmetic number, because the mean of its divisors is an integer number (31996091016).

Almost surely, 2^127980000781 is an apocalyptic number.

127980000781 is the 159988-th centered decagonal number.

It is an amenable number.

127980000781 is a deficient number, since it is larger than the sum of its proper divisors (4363283).

127980000781 is an equidigital number, since it uses as much as digits as its factorization.

127980000781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4363282.

The product of its (nonzero) digits is 56448, while the sum is 43.

The spelling of 127980000781 in words is "one hundred twenty-seven billion, nine hundred eighty million, seven hundred eighty-one", and thus it is an aban number.