640021052404421 has 2 divisors, whose sum is σ = 640021052404422. Its totient is φ = 640021052404420.

The previous prime is 640021052404411. The next prime is 640021052404463. The reversal of 640021052404421 is 124404250120046.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 611783370405025 + 28237681999396 = 24734255^2 + 5313914^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640021052404421 is a prime.

It is a super-2 number, since 2×640021052404421² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640021052404411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320010526202210 + 320010526202211.

It is an arithmetic number, because the mean of its divisors is an integer number (320010526202211).

Almost surely, 2^{640021052404421} is an apocalyptic number.

It is an amenable number.

640021052404421 is a deficient number, since it is larger than the sum of its proper divisors (1).

640021052404421 is an equidigital number, since it uses as much as digits as its factorization.

640021052404421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 61440, while the sum is 35.

The spelling of 640021052404421 in words is "six hundred forty trillion, twenty-one billion, fifty-two million, four hundred four thousand, four hundred twenty-one".