64687121 has 2 divisors, whose sum is σ = 64687122. Its totient is φ = 64687120.

The previous prime is 64687099. The next prime is 64687123. The reversal of 64687121 is 12178646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57456400 + 7230721 = 7580^2 + 2689^2 .

It is a cyclic number.

It is not a de Polignac number, because 64687121 - 2¹⁸ = 64424977 is a prime.

It is a Sophie Germain prime.

Together with 64687123, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (64687123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32343560 + 32343561.

It is an arithmetic number, because the mean of its divisors is an integer number (32343561).

Almost surely, 2^64687121 is an apocalyptic number.

It is an amenable number.

64687121 is a deficient number, since it is larger than the sum of its proper divisors (1).

64687121 is an equidigital number, since it uses as much as digits as its factorization.

64687121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 35.

The square root of 64687121 is about 8042.8304097500. The cubic root of 64687121 is about 401.4264094274.

The spelling of 64687121 in words is "sixty-four million, six hundred eighty-seven thousand, one hundred twenty-one".