21781714 has 16 divisors (see below), whose sum is σ = 34632000. Its totient is φ = 10245744.

The previous prime is 21781703. The next prime is 21781723. The reversal of 21781714 is 41718712.

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, 3739 + ... + 7585.

It is an arithmetic number, because the mean of its divisors is an integer number (2164500).

Almost surely, 2^21781714 is an apocalyptic number.

21781714 is a deficient number, since it is larger than the sum of its proper divisors (12850286).

21781714 is a wasteful number, since it uses less digits than its factorization.

21781714 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4017.

The product of its digits is 3136, while the sum is 31.

The square root of 21781714 is about 4667.0883857069. The cubic root of 21781714 is about 279.2741147046.

The spelling of 21781714 in words is "twenty-one million, seven hundred eighty-one thousand, seven hundred fourteen".