2665821989 has 2 divisors, whose sum is σ = 2665821990. Its totient is φ = 2665821988.

The previous prime is 2665821979. The next prime is 2665822007. The reversal of 2665821989 is 9891285662.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2623181089 + 42640900 = 51217^2 + 6530^2 .

It is a cyclic number.

It is not a de Polignac number, because 2665821989 - 2⁴ = 2665821973 is a prime.

It is a super-2 number, since 2×2665821989² = 14213213754071832242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2665821919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1332910994 + 1332910995.

It is an arithmetic number, because the mean of its divisors is an integer number (1332910995).

Almost surely, 2^2665821989 is an apocalyptic number.

It is an amenable number.

2665821989 is a deficient number, since it is larger than the sum of its proper divisors (1).

2665821989 is an equidigital number, since it uses as much as digits as its factorization.

2665821989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3732480, while the sum is 56.

The square root of 2665821989 is about 51631.5987453420. The cubic root of 2665821989 is about 1386.5761165433.

The spelling of 2665821989 in words is "two billion, six hundred sixty-five million, eight hundred twenty-one thousand, nine hundred eighty-nine".