198121778590 has 16 divisors (see below), whose sum is σ = 377596801872. Its totient is φ = 74587022464.

The previous prime is 198121778581. The next prime is 198121778593. The reversal of 198121778590 is 95877121891.

It is a super-3 number, since 3×198121778590³ (a number of 35 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (198121778593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 582710944 + ... + 582711283.

It is an arithmetic number, because the mean of its divisors is an integer number (23599800117).

Almost surely, 2^198121778590 is an apocalyptic number.

198121778590 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

198121778590 is a deficient number, since it is larger than the sum of its proper divisors (179475023282).

198121778590 is a wasteful number, since it uses less digits than its factorization.

198121778590 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1165422251.

The product of its (nonzero) digits is 2540160, while the sum is 58.

The spelling of 198121778590 in words is "one hundred ninety-eight billion, one hundred twenty-one million, seven hundred seventy-eight thousand, five hundred ninety".