121997820 has 48 divisors (see below), whose sum is σ = 390394368. Its totient is φ = 27885120.

The previous prime is 121997807. The next prime is 121997857. The reversal of 121997820 is 28799121.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 144816 + ... + 145655.

It is an arithmetic number, because the mean of its divisors is an integer number (8133216).

Almost surely, 2^121997820 is an apocalyptic number.

121997820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121997820 is an abundant number, since it is smaller than the sum of its proper divisors (268396548).

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

121997820 is a wasteful number, since it uses less digits than its factorization.

121997820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290490 (or 290488 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 121997820 is about 11045.2623327832. The cubic root of 121997820 is about 495.9646122429.

The spelling of 121997820 in words is "one hundred twenty-one million, nine hundred ninety-seven thousand, eight hundred twenty".