2779981 has 2 divisors, whose sum is σ = 2779982. Its totient is φ = 2779980.

The previous prime is 2779961. The next prime is 2779991. The reversal of 2779981 is 1899772.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1602756 + 1177225 = 1266^2 + 1085^2 .

It is a cyclic number.

It is not a de Polignac number, because 2779981 - 2⁵ = 2779949 is a prime.

It is a super-2 number, since 2×2779981² = 15456588720722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2779961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1389990 + 1389991.

It is an arithmetic number, because the mean of its divisors is an integer number (1389991).

2^2779981 is an apocalyptic number.

It is an amenable number.

2779981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2779981 is an equidigital number, since it uses as much as digits as its factorization.

2779981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 63504, while the sum is 43.

The square root of 2779981 is about 1667.3275023222. The cubic root of 2779981 is about 140.6092664537.

It can be divided in two parts, 27 and 79981, that added together give a palindrome (80008).

The spelling of 2779981 in words is "two million, seven hundred seventy-nine thousand, nine hundred eighty-one".