121191820 has 24 divisors (see below), whose sum is σ = 254855664. Its totient is φ = 48409536.

The previous prime is 121191809. The next prime is 121191857. The reversal of 121191820 is 28191121.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12139 + ... + 19741.

It is an arithmetic number, because the mean of its divisors is an integer number (10618986).

Almost surely, 2^121191820 is an apocalyptic number.

121191820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121191820 is an abundant number, since it is smaller than the sum of its proper divisors (133663844).

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

121191820 is a wasteful number, since it uses less digits than its factorization.

121191820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8409 (or 8407 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 25.

The square root of 121191820 is about 11008.7156380751. The cubic root of 121191820 is about 494.8699723090.

The spelling of 121191820 in words is "one hundred twenty-one million, one hundred ninety-one thousand, eight hundred twenty".