21709894 has 16 divisors (see below), whose sum is σ = 34398000. Its totient is φ = 10247904.

The previous prime is 21709879. The next prime is 21709903. The reversal of 21709894 is 49890712.

It is a congruent number.

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, 12444 + ... + 14080.

It is an arithmetic number, because the mean of its divisors is an integer number (2149875).

Almost surely, 2^21709894 is an apocalyptic number.

21709894 is a deficient number, since it is larger than the sum of its proper divisors (12688106).

21709894 is a wasteful number, since it uses less digits than its factorization.

21709894 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2007.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 21709894 is about 4659.3877280175. The cubic root of 21709894 is about 278.9668301586.

The spelling of 21709894 in words is "twenty-one million, seven hundred nine thousand, eight hundred ninety-four".