42768021 has 4 divisors (see below), whose sum is σ = 57024032. Its totient is φ = 28512012.

The previous prime is 42768013. The next prime is 42768023. The reversal of 42768021 is 12086724.

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 not a de Polignac number, because 42768021 - 2³ = 42768013 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 42768021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42768023) 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, 7128001 + ... + 7128006.

It is an arithmetic number, because the mean of its divisors is an integer number (14256008).

Almost surely, 2^42768021 is an apocalyptic number.

It is an amenable number.

42768021 is a deficient number, since it is larger than the sum of its proper divisors (14256011).

42768021 is a wasteful number, since it uses less digits than its factorization.

42768021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14256010.

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 42768021 is about 6539.7263704225. The cubic root of 42768021 is about 349.7086582332.

The spelling of 42768021 in words is "forty-two million, seven hundred sixty-eight thousand, twenty-one".