20685998 has 4 divisors (see below), whose sum is σ = 31029000. Its totient is φ = 10342998.

The previous prime is 20685983. The next prime is 20686009. The reversal of 20685998 is 89958602.

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

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, 5171498 + ... + 5171501.

It is an arithmetic number, because the mean of its divisors is an integer number (7757250).

Almost surely, 2^20685998 is an apocalyptic number.

20685998 is a deficient number, since it is larger than the sum of its proper divisors (10343002).

20685998 is a wasteful number, since it uses less digits than its factorization.

20685998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10343001.

The product of its (nonzero) digits is 311040, while the sum is 47.

The square root of 20685998 is about 4548.1862318951. The cubic root of 20685998 is about 274.5104148545.

The spelling of 20685998 in words is "twenty million, six hundred eighty-five thousand, nine hundred ninety-eight".