20917816 has 16 divisors (see below), whose sum is σ = 40573800. Its totient is φ = 10098144.

The previous prime is 20917811. The next prime is 20917829. The reversal of 20917816 is 61871902.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20917811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44850 + ... + 45313.

Almost surely, 2^20917816 is an apocalyptic number.

It is an amenable number.

20917816 is a deficient number, since it is larger than the sum of its proper divisors (19655984).

20917816 is a wasteful number, since it uses less digits than its factorization.

20917816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90198 (or 90194 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 20917816 is about 4573.5998950499. The cubic root of 20917816 is about 275.5320432688.

The spelling of 20917816 in words is "twenty million, nine hundred seventeen thousand, eight hundred sixteen".