127651991 has 2 divisors, whose sum is σ = 127651992. Its totient is φ = 127651990.

The previous prime is 127651949. The next prime is 127651999. The reversal of 127651991 is 199156721.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 127651991 - 2²⁶ = 60543127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (127651999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63825995 + 63825996.

It is an arithmetic number, because the mean of its divisors is an integer number (63825996).

Almost surely, 2^127651991 is an apocalyptic number.

127651991 is a deficient number, since it is larger than the sum of its proper divisors (1).

127651991 is an equidigital number, since it uses as much as digits as its factorization.

127651991 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 127651991 is about 11298.3180606673. The cubic root of 127651991 is about 503.5112722141.

The spelling of 127651991 in words is "one hundred twenty-seven million, six hundred fifty-one thousand, nine hundred ninety-one".