121721550 has 48 divisors (see below), whose sum is σ = 302540160. Its totient is φ = 32387040.

The previous prime is 121721539. The next prime is 121721591. The reversal of 121721550 is 55127121.

It is a super-2 number, since 2×121721550² = 29632271468805000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 121721550.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 131991 + ... + 132909.

It is an arithmetic number, because the mean of its divisors is an integer number (6302920).

Almost surely, 2^121721550 is an apocalyptic number.

121721550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

121721550 is an abundant number, since it is smaller than the sum of its proper divisors (180818610).

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

121721550 is a wasteful number, since it uses less digits than its factorization.

121721550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1817 (or 1812 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 24.

The square root of 121721550 is about 11032.7489774761. The cubic root of 121721550 is about 495.5899506210.

Adding to 121721550 its reverse (55127121), we get a palindrome (176848671).

The spelling of 121721550 in words is "one hundred twenty-one million, seven hundred twenty-one thousand, five hundred fifty".