6221028651661 has 2 divisors, whose sum is σ = 6221028651662. Its totient is φ = 6221028651660.

The previous prime is 6221028651653. The next prime is 6221028651703. The reversal of 6221028651661 is 1661568201226.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5016730917636 + 1204297734025 = 2239806^2 + 1097405^2 .

It is a cyclic number.

It is not a de Polignac number, because 6221028651661 - 2³ = 6221028651653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6221028654661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3110514325830 + 3110514325831.

It is an arithmetic number, because the mean of its divisors is an integer number (3110514325831).

Almost surely, 2^{6221028651661} is an apocalyptic number.

It is an amenable number.

6221028651661 is a deficient number, since it is larger than the sum of its proper divisors (1).

6221028651661 is an equidigital number, since it uses as much as digits as its factorization.

6221028651661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 414720, while the sum is 46.

The spelling of 6221028651661 in words is "six trillion, two hundred twenty-one billion, twenty-eight million, six hundred fifty-one thousand, six hundred sixty-one".