42661643 has 2 divisors, whose sum is σ = 42661644. Its totient is φ = 42661642.

The previous prime is 42661621. The next prime is 42661651. The reversal of 42661643 is 34616624.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 42661643 - 2¹⁶ = 42596107 is a prime.

It is not a weakly prime, because it can be changed into another prime (42661243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21330821 + 21330822.

It is an arithmetic number, because the mean of its divisors is an integer number (21330822).

Almost surely, 2^42661643 is an apocalyptic number.

42661643 is a deficient number, since it is larger than the sum of its proper divisors (1).

42661643 is an equidigital number, since it uses as much as digits as its factorization.

42661643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 32.

The square root of 42661643 is about 6531.5880917278. The cubic root of 42661643 is about 349.4184710529.

The spelling of 42661643 in words is "forty-two million, six hundred sixty-one thousand, six hundred forty-three".