199121961528 has 256 divisors, whose sum is σ = 650845440000. Its totient is φ = 55222041600.

The previous prime is 199121961527. The next prime is 199121961539. The reversal of 199121961528 is 825169121991.

199121961528 is a `hidden beast` number, since 1 + 9 + 9 + 1 + 2 + 19 + 615 + 2 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199121961523) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12328338 + ... + 12344478.

It is an arithmetic number, because the mean of its divisors is an integer number (2542365000).

Almost surely, 2^199121961528 is an apocalyptic number.

199121961528 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 199121961528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (325422720000).

199121961528 is an abundant number, since it is smaller than the sum of its proper divisors (451723478472).

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

199121961528 is a wasteful number, since it uses less digits than its factorization.

199121961528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16403 (or 16393 counting only the distinct ones).

The product of its digits is 699840, while the sum is 54.

The spelling of 199121961528 in words is "one hundred ninety-nine billion, one hundred twenty-one million, nine hundred sixty-one thousand, five hundred twenty-eight".