121561550 has 24 divisors (see below), whose sum is σ = 246660552. Its totient is φ = 44204000.

The previous prime is 121561549. The next prime is 121561579. The reversal of 121561550 is 55165121.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 109961 + ... + 111060.

It is an arithmetic number, because the mean of its divisors is an integer number (10277523).

Almost surely, 2^121561550 is an apocalyptic number.

121561550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

121561550 is an abundant number, since it is smaller than the sum of its proper divisors (125099002).

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

121561550 is a wasteful number, since it uses less digits than its factorization.

121561550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221044 (or 221039 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 26.

The square root of 121561550 is about 11025.4954537200. The cubic root of 121561550 is about 495.3727084509.

The spelling of 121561550 in words is "one hundred twenty-one million, five hundred sixty-one thousand, five hundred fifty".