42665966956621 has 2 divisors, whose sum is σ = 42665966956622. Its totient is φ = 42665966956620.

The previous prime is 42665966956609. The next prime is 42665966956651. The reversal of 42665966956621 is 12665966956624.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 39586608820521 + 3079358136100 = 6291789^2 + 1754810^2 .

It is a cyclic number.

It is not a de Polignac number, because 42665966956621 - 2⁷ = 42665966956493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42665966956651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21332983478310 + 21332983478311.

It is an arithmetic number, because the mean of its divisors is an integer number (21332983478311).

Almost surely, 2^{42665966956621} is an apocalyptic number.

It is an amenable number.

42665966956621 is a deficient number, since it is larger than the sum of its proper divisors (1).

42665966956621 is an equidigital number, since it uses as much as digits as its factorization.

42665966956621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1511654400, while the sum is 73.

The spelling of 42665966956621 in words is "forty-two trillion, six hundred sixty-five billion, nine hundred sixty-six million, nine hundred fifty-six thousand, six hundred twenty-one".