42688821 has 16 divisors (see below), whose sum is σ = 65968128. Its totient is φ = 24049200.

The previous prime is 42688817. The next prime is 42688843. The reversal of 42688821 is 12888624.

It is not a de Polignac number, because 42688821 - 2² = 42688817 is a prime.

It is a super-3 number, since 3×42688821³ (a number of 24 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 42688821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42688021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12825 + ... + 15806.

It is an arithmetic number, because the mean of its divisors is an integer number (4123008).

Almost surely, 2^42688821 is an apocalyptic number.

It is an amenable number.

42688821 is a deficient number, since it is larger than the sum of its proper divisors (23279307).

42688821 is a wasteful number, since it uses less digits than its factorization.

42688821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28712.

The product of its digits is 49152, while the sum is 39.

The square root of 42688821 is about 6533.6682652244. The cubic root of 42688821 is about 349.4926554071.

The spelling of 42688821 in words is "forty-two million, six hundred eighty-eight thousand, eight hundred twenty-one".