21788042 has 16 divisors (see below), whose sum is σ = 33999360. Its totient is φ = 10462608.

The previous prime is 21788029. The next prime is 21788083. The reversal of 21788042 is 24088712.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3983 + ... + 7709.

It is an arithmetic number, because the mean of its divisors is an integer number (2124960).

Almost surely, 2^21788042 is an apocalyptic number.

21788042 is a deficient number, since it is larger than the sum of its proper divisors (12211318).

21788042 is a wasteful number, since it uses less digits than its factorization.

21788042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3845.

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 21788042 is about 4667.7662752113. The cubic root of 21788042 is about 279.3011568907.

The spelling of 21788042 in words is "twenty-one million, seven hundred eighty-eight thousand, forty-two".