2621918261 has 2 divisors, whose sum is σ = 2621918262. Its totient is φ = 2621918260.

The previous prime is 2621918237. The next prime is 2621918269. The reversal of 2621918261 is 1628191262.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2460755236 + 161163025 = 49606^2 + 12695^2 .

It is a cyclic number.

It is not a de Polignac number, because 2621918261 - 2⁶ = 2621918197 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2621918269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1310959130 + 1310959131.

It is an arithmetic number, because the mean of its divisors is an integer number (1310959131).

Almost surely, 2^2621918261 is an apocalyptic number.

It is an amenable number.

2621918261 is a deficient number, since it is larger than the sum of its proper divisors (1).

2621918261 is an equidigital number, since it uses as much as digits as its factorization.

2621918261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 38.

The square root of 2621918261 is about 51204.6703045728. The cubic root of 2621918261 is about 1378.9220492306.

The spelling of 2621918261 in words is "two billion, six hundred twenty-one million, nine hundred eighteen thousand, two hundred sixty-one".