42528721 has 4 divisors (see below), whose sum is σ = 42783552. Its totient is φ = 42273892.

The previous prime is 42528671. The next prime is 42528751. The reversal of 42528721 is 12782524.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42528721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42528751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127165 + ... + 127498.

It is an arithmetic number, because the mean of its divisors is an integer number (10695888).

Almost surely, 2^42528721 is an apocalyptic number.

It is an amenable number.

42528721 is a deficient number, since it is larger than the sum of its proper divisors (254831).

42528721 is a wasteful number, since it uses less digits than its factorization.

42528721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254830.

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

The square root of 42528721 is about 6521.4048333162. The cubic root of 42528721 is about 349.0551960713.

The spelling of 42528721 in words is "forty-two million, five hundred twenty-eight thousand, seven hundred twenty-one".