20998566 has 24 divisors (see below), whose sum is σ = 46466784. Its totient is φ = 6850320.

The previous prime is 20998531. The next prime is 20998583. The reversal of 20998566 is 66589902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11565 + ... + 13256.

It is an arithmetic number, because the mean of its divisors is an integer number (1936116).

Almost surely, 2^20998566 is an apocalyptic number.

20998566 is an abundant number, since it is smaller than the sum of its proper divisors (25468218).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20998566 is a wasteful number, since it uses less digits than its factorization.

20998566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24876 (or 24873 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 20998566 is about 4582.4192300574. The cubic root of 20998566 is about 275.8861376582.

The spelling of 20998566 in words is "twenty million, nine hundred ninety-eight thousand, five hundred sixty-six".