20989646 has 4 divisors (see below), whose sum is σ = 31484472. Its totient is φ = 10494822.

The previous prime is 20989627. The next prime is 20989651. The reversal of 20989646 is 64698902.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 20989597 and 20989606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5247410 + ... + 5247413.

It is an arithmetic number, because the mean of its divisors is an integer number (7871118).

Almost surely, 2^20989646 is an apocalyptic number.

20989646 is a deficient number, since it is larger than the sum of its proper divisors (10494826).

20989646 is a wasteful number, since it uses less digits than its factorization.

20989646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10494825.

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 20989646 is about 4581.4458416530. The cubic root of 20989646 is about 275.8470674842.

The spelling of 20989646 in words is "twenty million, nine hundred eighty-nine thousand, six hundred forty-six".