6978553981 has 6 divisors (see below), whose sum is σ = 8117909790. Its totient is φ = 5981617656.

The previous prime is 6978553973. The next prime is 6978554021. The reversal of 6978553981 is 1893558796.

It can be written as a sum of positive squares in only one way, i.e., 5313097881 + 1665456100 = 72891^2 + 40810^2 .

It is not a de Polignac number, because 6978553981 - 2³ = 6978553973 is a prime.

It is a super-2 number, since 2×6978553981² = 97400431331461896722, which 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 (6978553381) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 71209686 + ... + 71209783.

It is an arithmetic number, because the mean of its divisors is an integer number (1352984965).

Almost surely, 2^6978553981 is an apocalyptic number.

It is an amenable number.

6978553981 is a deficient number, since it is larger than the sum of its proper divisors (1139355809).

6978553981 is a wasteful number, since it uses less digits than its factorization.

6978553981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142419483 (or 142419476 counting only the distinct ones).

The product of its digits is 16329600, while the sum is 61.

The square root of 6978553981 is about 83537.7398604966. The cubic root of 6978553981 is about 1910.9756243900.

The spelling of 6978553981 in words is "six billion, nine hundred seventy-eight million, five hundred fifty-three thousand, nine hundred eighty-one".