6247945168921 has 3 divisors (see below), whose sum is σ = 6247947668511. Its totient is φ = 6247942669332.

The previous prime is 6247945168807. The next prime is 6247945168939. The reversal of 6247945168921 is 1298615497426.

The square root of 6247945168921 is 2499589.

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., 5814796909321 + 433148259600 = 2411389^2 + 658140^2 .

It is a de Polignac number, because none of the positive numbers 2^k-6247945168921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6247945168721) 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, 1249795 + ... + 3749383.

It is an arithmetic number, because the mean of its divisors is an integer number (2082649222837).

Almost surely, 2^{6247945168921} is an apocalyptic number.

6247945168921 is the 2499589-th square number.

6247945168921 is the 1249795-th centered octagonal number.

It is an amenable number.

6247945168921 is a deficient number, since it is larger than the sum of its proper divisors (2499590).

6247945168921 is an frugal number, since it uses more digits than its factorization.

6247945168921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4999178 (or 2499589 counting only the distinct ones).

The product of its digits is 52254720, while the sum is 64.

Multiplying 6247945168921 by its sum of digits (64), we get a square (399868490810944 = 19996712²).

The spelling of 6247945168921 in words is "six trillion, two hundred forty-seven billion, nine hundred forty-five million, one hundred sixty-eight thousand, nine hundred twenty-one".