2578765421 has 2 divisors, whose sum is σ = 2578765422. Its totient is φ = 2578765420.

The previous prime is 2578765363. The next prime is 2578765457. The reversal of 2578765421 is 1245678752.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2392579396 + 186186025 = 48914^2 + 13645^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2578765421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2578761421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1289382710 + 1289382711.

It is an arithmetic number, because the mean of its divisors is an integer number (1289382711).

Almost surely, 2^2578765421 is an apocalyptic number.

It is an amenable number.

2578765421 is a deficient number, since it is larger than the sum of its proper divisors (1).

2578765421 is an equidigital number, since it uses as much as digits as its factorization.

2578765421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 940800, while the sum is 47.

The square root of 2578765421 is about 50781.5460674446. The cubic root of 2578765421 is about 1371.3151668189.

It can be divided in two parts, 257 and 8765421, that added together give a palindrome (8765678).

The spelling of 2578765421 in words is "two billion, five hundred seventy-eight million, seven hundred sixty-five thousand, four hundred twenty-one".