6245305881721 has 3 divisors (see below), whose sum is σ = 6245308380783. Its totient is φ = 6245303382660.

The previous prime is 6245305881701. The next prime is 6245305881739. The reversal of 6245305881721 is 1271885035426.

The square root of 6245305881721 is 2499061.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 3216244105321 + 3029061776400 = 1793389^2 + 1740420^2 .

It is not a de Polignac number, because 6245305881721 - 2³¹ = 6243158398073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6245305881701) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 1249531 + ... + 3748591.

It is an arithmetic number, because the mean of its divisors is an integer number (2081769460261).

Almost surely, 2^{6245305881721} is an apocalyptic number.

6245305881721 is the 2499061-st square number.

6245305881721 is the 1249531-st centered octagonal number.

It is an amenable number.

6245305881721 is a deficient number, since it is larger than the sum of its proper divisors (2499062).

6245305881721 is an frugal number, since it uses more digits than its factorization.

6245305881721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4998122 (or 2499061 counting only the distinct ones).

The product of its (nonzero) digits is 3225600, while the sum is 52.

The spelling of 6245305881721 in words is "six trillion, two hundred forty-five billion, three hundred five million, eight hundred eighty-one thousand, seven hundred twenty-one".