126308728921 has 2 divisors, whose sum is σ = 126308728922. Its totient is φ = 126308728920.

The previous prime is 126308728877. The next prime is 126308728963. The reversal of 126308728921 is 129827803621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78058213321 + 48250515600 = 279389^2 + 219660^2 .

It is a cyclic number.

It is not a de Polignac number, because 126308728921 - 2¹⁵ = 126308696153 is a prime.

It is not a weakly prime, because it can be changed into another prime (126308728321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63154364460 + 63154364461.

It is an arithmetic number, because the mean of its divisors is an integer number (63154364461).

Almost surely, 2^126308728921 is an apocalyptic number.

It is an amenable number.

126308728921 is a deficient number, since it is larger than the sum of its proper divisors (1).

126308728921 is an equidigital number, since it uses as much as digits as its factorization.

126308728921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 580608, while the sum is 49.

The spelling of 126308728921 in words is "one hundred twenty-six billion, three hundred eight million, seven hundred twenty-eight thousand, nine hundred twenty-one".