21706604 has 6 divisors (see below), whose sum is σ = 37986564. Its totient is φ = 10853300.

The previous prime is 21706591. The next prime is 21706609. The reversal of 21706604 is 40660712.

It is not an unprimeable number, because it can be changed into a prime (21706609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2713322 + ... + 2713329.

It is an arithmetic number, because the mean of its divisors is an integer number (6331094).

Almost surely, 2^21706604 is an apocalyptic number.

It is an amenable number.

21706604 is a deficient number, since it is larger than the sum of its proper divisors (16279960).

21706604 is a wasteful number, since it uses less digits than its factorization.

21706604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5426655 (or 5426653 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 21706604 is about 4659.0346639621. The cubic root of 21706604 is about 278.9527375482.

The spelling of 21706604 in words is "twenty-one million, seven hundred six thousand, six hundred four".