126715991 has 2 divisors, whose sum is σ = 126715992. Its totient is φ = 126715990.

The previous prime is 126715973. The next prime is 126715999. The reversal of 126715991 is 199517621.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-126715991 is a prime.

It is a super-2 number, since 2×126715991² = 32113884750224162, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (126715999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63357995 + 63357996.

It is an arithmetic number, because the mean of its divisors is an integer number (63357996).

Almost surely, 2^126715991 is an apocalyptic number.

126715991 is a deficient number, since it is larger than the sum of its proper divisors (1).

126715991 is an equidigital number, since it uses as much as digits as its factorization.

126715991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34020, while the sum is 41.

The square root of 126715991 is about 11256.8197551529. The cubic root of 126715991 is about 502.2775973474.

The spelling of 126715991 in words is "one hundred twenty-six million, seven hundred fifteen thousand, nine hundred ninety-one".