21651421022597 has 2 divisors, whose sum is σ = 21651421022598. Its totient is φ = 21651421022596.

The previous prime is 21651421022551. The next prime is 21651421022653. The reversal of 21651421022597 is 79522012415612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14282156122276 + 7369264900321 = 3779174^2 + 2714639^2 .

It is a cyclic number.

It is not a de Polignac number, because 21651421022597 - 2⁶ = 21651421022533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21651421022537) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825710511298 + 10825710511299.

It is an arithmetic number, because the mean of its divisors is an integer number (10825710511299).

Almost surely, 2^{21651421022597} is an apocalyptic number.

It is an amenable number.

21651421022597 is a deficient number, since it is larger than the sum of its proper divisors (1).

21651421022597 is an equidigital number, since it uses as much as digits as its factorization.

21651421022597 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 604800, while the sum is 47.

The spelling of 21651421022597 in words is "twenty-one trillion, six hundred fifty-one billion, four hundred twenty-one million, twenty-two thousand, five hundred ninety-seven".