2645877821 has 2 divisors, whose sum is σ = 2645877822. Its totient is φ = 2645877820.

The previous prime is 2645877779. The next prime is 2645877823. The reversal of 2645877821 is 1287785462.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1516245721 + 1129632100 = 38939^2 + 33610^2 .

It is a cyclic number.

It is not a de Polignac number, because 2645877821 - 2⁶ = 2645877757 is a prime.

Together with 2645877823, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2645877821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2645877823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1322938910 + 1322938911.

It is an arithmetic number, because the mean of its divisors is an integer number (1322938911).

Almost surely, 2^2645877821 is an apocalyptic number.

It is an amenable number.

2645877821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2645877821 is an equidigital number, since it uses as much as digits as its factorization.

2645877821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1505280, while the sum is 50.

The square root of 2645877821 is about 51438.0969807399. The cubic root of 2645877821 is about 1383.1095986090.

The spelling of 2645877821 in words is "two billion, six hundred forty-five million, eight hundred seventy-seven thousand, eight hundred twenty-one".