20913668 has 6 divisors (see below), whose sum is σ = 36598926. Its totient is φ = 10456832.

The previous prime is 20913643. The next prime is 20913707. The reversal of 20913668 is 86631902.

It can be written as a sum of positive squares in only one way, i.e., 20052484 + 861184 = 4478^2 + 928^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2614205 + ... + 2614212.

It is an arithmetic number, because the mean of its divisors is an integer number (6099821).

Almost surely, 2^20913668 is an apocalyptic number.

It is an amenable number.

20913668 is a deficient number, since it is larger than the sum of its proper divisors (15685258).

20913668 is a wasteful number, since it uses less digits than its factorization.

20913668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5228421 (or 5228419 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 20913668 is about 4573.1464004556. The cubic root of 20913668 is about 275.5138294096.

The spelling of 20913668 in words is "twenty million, nine hundred thirteen thousand, six hundred sixty-eight".