126405661 has 2 divisors, whose sum is σ = 126405662. Its totient is φ = 126405660.

The previous prime is 126405649. The next prime is 126405673. The reversal of 126405661 is 166504621.

It is a balanced prime because it is at equal distance from previous prime (126405649) and next prime (126405673).

It can be written as a sum of positive squares in only one way, i.e., 103652761 + 22752900 = 10181^2 + 4770^2 .

It is an emirp because it is prime and its reverse (166504621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 126405661 - 2⁷ = 126405533 is a prime.

It is a super-2 number, since 2×126405661² = 31956782265693842, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (126405691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63202830 + 63202831.

It is an arithmetic number, because the mean of its divisors is an integer number (63202831).

Almost surely, 2^126405661 is an apocalyptic number.

It is an amenable number.

126405661 is a deficient number, since it is larger than the sum of its proper divisors (1).

126405661 is an equidigital number, since it uses as much as digits as its factorization.

126405661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 126405661 is about 11243.0272169020. The cubic root of 126405661 is about 501.8672328692.

The spelling of 126405661 in words is "one hundred twenty-six million, four hundred five thousand, six hundred sixty-one".