1266440621 has 2 divisors, whose sum is σ = 1266440622. Its totient is φ = 1266440620.

The previous prime is 1266440599. The next prime is 1266440627. The reversal of 1266440621 is 1260446621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 712356100 + 554084521 = 26690^2 + 23539^2 .

It is a cyclic number.

It is not a de Polignac number, because 1266440621 - 2²² = 1262246317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1266440627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 633220310 + 633220311.

It is an arithmetic number, because the mean of its divisors is an integer number (633220311).

Almost surely, 2^1266440621 is an apocalyptic number.

It is an amenable number.

1266440621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1266440621 is an equidigital number, since it uses as much as digits as its factorization.

1266440621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 1266440621 is about 35587.0850309491. The cubic root of 1266440621 is about 1081.9194891252.

The spelling of 1266440621 in words is "one billion, two hundred sixty-six million, four hundred forty thousand, six hundred twenty-one".