2665139021 has 2 divisors, whose sum is σ = 2665139022. Its totient is φ = 2665139020.

The previous prime is 2665138981. The next prime is 2665139033. The reversal of 2665139021 is 1209315662.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2626562500 + 38576521 = 51250^2 + 6211^2 .

It is a cyclic number.

It is not a de Polignac number, because 2665139021 - 2²² = 2660944717 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2665139041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1332569510 + 1332569511.

It is an arithmetic number, because the mean of its divisors is an integer number (1332569511).

Almost surely, 2^2665139021 is an apocalyptic number.

It is an amenable number.

2665139021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2665139021 is an equidigital number, since it uses as much as digits as its factorization.

2665139021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 2665139021 is about 51624.9844648887. The cubic root of 2665139021 is about 1386.4576955331.

The spelling of 2665139021 in words is "two billion, six hundred sixty-five million, one hundred thirty-nine thousand, twenty-one".