64812121961 has 2 divisors, whose sum is σ = 64812121962. Its totient is φ = 64812121960.

The previous prime is 64812121873. The next prime is 64812121967. The reversal of 64812121961 is 16912121846.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63393168400 + 1418953561 = 251780^2 + 37669^2 .

It is a cyclic number.

It is not a de Polignac number, because 64812121961 - 2¹⁴ = 64812105577 is a prime.

It is a super-2 number, since 2×64812121961² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (64812121967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32406060980 + 32406060981.

It is an arithmetic number, because the mean of its divisors is an integer number (32406060981).

Almost surely, 2^64812121961 is an apocalyptic number.

It is an amenable number.

64812121961 is a deficient number, since it is larger than the sum of its proper divisors (1).

64812121961 is an equidigital number, since it uses as much as digits as its factorization.

64812121961 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 41.

The spelling of 64812121961 in words is "sixty-four billion, eight hundred twelve million, one hundred twenty-one thousand, nine hundred sixty-one".