2078617981 has 6 divisors (see below), whose sum is σ = 2284762046. Its totient is φ = 1889652600.

The previous prime is 2078617969. The next prime is 2078618021. The reversal of 2078617981 is 1897168702.

It can be written as a sum of positive squares in only one way, i.e., 1984702500 + 93915481 = 44550^2 + 9691^2 .

It is not a de Polignac number, because 2078617981 - 2¹⁷ = 2078486909 is a prime.

It is a super-2 number, since 2×2078617981² = 8641305421873032722, 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 (2078617951) 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, 8589210 + ... + 8589451.

Almost surely, 2^2078617981 is an apocalyptic number.

It is an amenable number.

2078617981 is a deficient number, since it is larger than the sum of its proper divisors (206144065).

2078617981 is a wasteful number, since it uses less digits than its factorization.

2078617981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17178683 (or 17178672 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 49.

The square root of 2078617981 is about 45591.8631007771. The cubic root of 2078617981 is about 1276.2180810372.

The spelling of 2078617981 in words is "two billion, seventy-eight million, six hundred seventeen thousand, nine hundred eighty-one".