621661441 has 2 divisors, whose sum is σ = 621661442. Its totient is φ = 621661440.

The previous prime is 621661427. The next prime is 621661463. The reversal of 621661441 is 144166126.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 543869041 + 77792400 = 23321^2 + 8820^2 .

It is a cyclic number.

It is not a de Polignac number, because 621661441 - 2¹⁷ = 621530369 is a prime.

It is not a weakly prime, because it can be changed into another prime (621601441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310830720 + 310830721.

It is an arithmetic number, because the mean of its divisors is an integer number (310830721).

Almost surely, 2^621661441 is an apocalyptic number.

It is an amenable number.

621661441 is a deficient number, since it is larger than the sum of its proper divisors (1).

621661441 is an equidigital number, since it uses as much as digits as its factorization.

621661441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 31.

The square root of 621661441 is about 24933.1394132388. The cubic root of 621661441 is about 853.4628931124.

The spelling of 621661441 in words is "six hundred twenty-one million, six hundred sixty-one thousand, four hundred forty-one".