21717946 has 16 divisors (see below), whose sum is σ = 33784128. Its totient is φ = 10463200.

The previous prime is 21717937. The next prime is 21717953. The reversal of 21717946 is 64971712.

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, 5211 + ... + 8401.

It is an arithmetic number, because the mean of its divisors is an integer number (2111508).

Almost surely, 2^21717946 is an apocalyptic number.

21717946 is a deficient number, since it is larger than the sum of its proper divisors (12066182).

21717946 is a wasteful number, since it uses less digits than its factorization.

21717946 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3317.

The product of its digits is 21168, while the sum is 37.

The square root of 21717946 is about 4660.2517099401. The cubic root of 21717946 is about 279.0013146395.

The spelling of 21717946 in words is "twenty-one million, seven hundred seventeen thousand, nine hundred forty-six".