20521998 has 40 divisors (see below), whose sum is σ = 52556592. Its totient is φ = 5863104.

The previous prime is 20521987. The next prime is 20522023. The reversal of 20521998 is 89912502.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7915 + ... + 10182.

Almost surely, 2^20521998 is an apocalyptic number.

20521998 is an abundant number, since it is smaller than the sum of its proper divisors (32034594).

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

20521998 is a wasteful number, since it uses less digits than its factorization.

20521998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18118 (or 18109 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 20521998 is about 4530.1211904319. The cubic root of 20521998 is about 273.7830434873.

The spelling of 20521998 in words is "twenty million, five hundred twenty-one thousand, nine hundred ninety-eight".