42725821 has 2 divisors, whose sum is σ = 42725822. Its totient is φ = 42725820.

The previous prime is 42725819. The next prime is 42725863. The reversal of 42725821 is 12852724.

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., 27941796 + 14784025 = 5286^2 + 3845^2 .

It is a cyclic number.

It is not a de Polignac number, because 42725821 - 2¹ = 42725819 is a prime.

Together with 42725819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42725621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21362910 + 21362911.

It is an arithmetic number, because the mean of its divisors is an integer number (21362911).

Almost surely, 2^42725821 is an apocalyptic number.

It is an amenable number.

42725821 is a deficient number, since it is larger than the sum of its proper divisors (1).

42725821 is an equidigital number, since it uses as much as digits as its factorization.

42725821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8960, while the sum is 31.

The square root of 42725821 is about 6536.4991394477. The cubic root of 42725821 is about 349.5935990403.

The spelling of 42725821 in words is "forty-two million, seven hundred twenty-five thousand, eight hundred twenty-one".