198590821 has 32 divisors (see below), whose sum is σ = 249129216. Its totient is φ = 155520000.

The previous prime is 198590801. The next prime is 198590837. The reversal of 198590821 is 128095891.

198590821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a 5-Lehmer number, since φ(198590821) divides (198590821-1)⁵.

It is a cyclic number.

It is not a de Polignac number, because 198590821 - 2¹⁵ = 198558053 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198590801) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 366811 + ... + 367351.

It is an arithmetic number, because the mean of its divisors is an integer number (7785288).

Almost surely, 2^198590821 is an apocalyptic number.

198590821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

198590821 is a deficient number, since it is larger than the sum of its proper divisors (50538395).

198590821 is a wasteful number, since it uses less digits than its factorization.

198590821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 733.

The product of its (nonzero) digits is 51840, while the sum is 43.

The square root of 198590821 is about 14092.2255517005. The cubic root of 198590821 is about 583.4268210074.

The spelling of 198590821 in words is "one hundred ninety-eight million, five hundred ninety thousand, eight hundred twenty-one".