81277121 has 2 divisors, whose sum is σ = 81277122. Its totient is φ = 81277120.

The previous prime is 81277103. The next prime is 81277127. The reversal of 81277121 is 12177218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64963600 + 16313521 = 8060^2 + 4039^2 .

It is a cyclic number.

It is not a de Polignac number, because 81277121 - 2¹⁸ = 81014977 is a prime.

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 (81277127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40638560 + 40638561.

It is an arithmetic number, because the mean of its divisors is an integer number (40638561).

Almost surely, 2^81277121 is an apocalyptic number.

It is an amenable number.

81277121 is a deficient number, since it is larger than the sum of its proper divisors (1).

81277121 is an equidigital number, since it uses as much as digits as its factorization.

81277121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1568, while the sum is 29.

The square root of 81277121 is about 9015.3824655419. The cubic root of 81277121 is about 433.1677386341.

The spelling of 81277121 in words is "eighty-one million, two hundred seventy-seven thousand, one hundred twenty-one".