126991961 has 2 divisors, whose sum is σ = 126991962. Its totient is φ = 126991960.

The previous prime is 126991939. The next prime is 126992051. The reversal of 126991961 is 169199621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 126990361 + 1600 = 11269^2 + 40^2 .

It is an emirp because it is prime and its reverse (169199621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 126991961 - 2⁶ = 126991897 is a prime.

It is a super-2 number, since 2×126991961² = 32253916317251042, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (126991561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63495980 + 63495981.

It is an arithmetic number, because the mean of its divisors is an integer number (63495981).

Almost surely, 2^126991961 is an apocalyptic number.

It is an amenable number.

126991961 is a deficient number, since it is larger than the sum of its proper divisors (1).

126991961 is an equidigital number, since it uses as much as digits as its factorization.

126991961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52488, while the sum is 44.

The square root of 126991961 is about 11269.0709909912. The cubic root of 126991961 is about 502.6419634703.

The spelling of 126991961 in words is "one hundred twenty-six million, nine hundred ninety-one thousand, nine hundred sixty-one".