640321421321473 has 2 divisors, whose sum is σ = 640321421321474. Its totient is φ = 640321421321472.

The previous prime is 640321421321429. The next prime is 640321421321507. The reversal of 640321421321473 is 374123124123046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 477173092981264 + 163148328340209 = 21844292^2 + 12772953^2 .

It is a cyclic number.

It is not a de Polignac number, because 640321421321473 - 2¹³ = 640321421313281 is a prime.

It is a super-2 number, since 2×640321421321473² (a number of 30 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (640321421621473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320160710660736 + 320160710660737.

It is an arithmetic number, because the mean of its divisors is an integer number (320160710660737).

Almost surely, 2^{640321421321473} is an apocalyptic number.

It is an amenable number.

640321421321473 is a deficient number, since it is larger than the sum of its proper divisors (1).

640321421321473 is an equidigital number, since it uses as much as digits as its factorization.

640321421321473 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 580608, while the sum is 43.

The spelling of 640321421321473 in words is "six hundred forty trillion, three hundred twenty-one billion, four hundred twenty-one million, three hundred twenty-one thousand, four hundred seventy-three".