121720110 has 32 divisors (see below), whose sum is σ = 292626432. Its totient is φ = 32403360.

The previous prime is 121720073. The next prime is 121720129. The reversal of 121720110 is 11027121.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 121720110.

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 15 ways as a sum of consecutive naturals, for example, 16275 + ... + 22545.

It is an arithmetic number, because the mean of its divisors is an integer number (9144576).

Almost surely, 2^121720110 is an apocalyptic number.

121720110 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

121720110 is an abundant number, since it is smaller than the sum of its proper divisors (170906322).

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

121720110 is a wasteful number, since it uses less digits than its factorization.

121720110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6928.

The product of its (nonzero) digits is 28, while the sum is 15.

The square root of 121720110 is about 11032.6837170291. The cubic root of 121720110 is about 495.5879962906.

Adding to 121720110 its reverse (11027121), we get a palindrome (132747231).

The spelling of 121720110 in words is "one hundred twenty-one million, seven hundred twenty thousand, one hundred ten".