64916729021 has 2 divisors, whose sum is σ = 64916729022. Its totient is φ = 64916729020.

The previous prime is 64916728999. The next prime is 64916729027. The reversal of 64916729021 is 12092761946.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62182903225 + 2733825796 = 249365^2 + 52286^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-64916729021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64916729027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32458364510 + 32458364511.

It is an arithmetic number, because the mean of its divisors is an integer number (32458364511).

Almost surely, 2^64916729021 is an apocalyptic number.

It is an amenable number.

64916729021 is a deficient number, since it is larger than the sum of its proper divisors (1).

64916729021 is an equidigital number, since it uses as much as digits as its factorization.

64916729021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 326592, while the sum is 47.

The spelling of 64916729021 in words is "sixty-four billion, nine hundred sixteen million, seven hundred twenty-nine thousand, twenty-one".