127720421 has 2 divisors, whose sum is σ = 127720422. Its totient is φ = 127720420.

The previous prime is 127720381. The next prime is 127720477. The reversal of 127720421 is 124027721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 116424100 + 11296321 = 10790^2 + 3361^2 .

It is a cyclic number.

It is not a de Polignac number, because 127720421 - 2¹⁴ = 127704037 is a prime.

It is a Chen prime.

It is equal to p_7256024 and since 127720421 and 7256024 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (127720121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 63860210 + 63860211.

It is an arithmetic number, because the mean of its divisors is an integer number (63860211).

Almost surely, 2^127720421 is an apocalyptic number.

It is an amenable number.

127720421 is a deficient number, since it is larger than the sum of its proper divisors (1).

127720421 is an equidigital number, since it uses as much as digits as its factorization.

127720421 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1568, while the sum is 26.

The square root of 127720421 is about 11301.3459817846. The cubic root of 127720421 is about 503.6012280415.

The spelling of 127720421 in words is "one hundred twenty-seven million, seven hundred twenty thousand, four hundred twenty-one".