42547721 has 2 divisors, whose sum is σ = 42547722. Its totient is φ = 42547720.

The previous prime is 42547693. The next prime is 42547751. The reversal of 42547721 is 12774524.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25000000 + 17547721 = 5000^2 + 4189^2 .

It is a cyclic number.

It is not a de Polignac number, because 42547721 - 2¹⁰ = 42546697 is a prime.

It is not a weakly prime, because it can be changed into another prime (42547751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21273860 + 21273861.

It is an arithmetic number, because the mean of its divisors is an integer number (21273861).

Almost surely, 2^42547721 is an apocalyptic number.

It is an amenable number.

42547721 is a deficient number, since it is larger than the sum of its proper divisors (1).

42547721 is an equidigital number, since it uses as much as digits as its factorization.

42547721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15680, while the sum is 32.

The square root of 42547721 is about 6522.8614119878. The cubic root of 42547721 is about 349.1071692726.

The spelling of 42547721 in words is "forty-two million, five hundred forty-seven thousand, seven hundred twenty-one".