198634029821 has 4 divisors (see below), whose sum is σ = 198823026144. Its totient is φ = 198445033500.

The previous prime is 198634029809. The next prime is 198634029823. The reversal of 198634029821 is 128920436891.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-198634029821 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 (198634029823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94496585 + ... + 94498686.

It is an arithmetic number, because the mean of its divisors is an integer number (49705756536).

Almost surely, 2^198634029821 is an apocalyptic number.

It is an amenable number.

198634029821 is a deficient number, since it is larger than the sum of its proper divisors (188996323).

198634029821 is a wasteful number, since it uses less digits than its factorization.

198634029821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188996322.

The product of its (nonzero) digits is 1492992, while the sum is 53.

The spelling of 198634029821 in words is "one hundred ninety-eight billion, six hundred thirty-four million, twenty-nine thousand, eight hundred twenty-one".