121221729 has 12 divisors (see below), whose sum is σ = 184314000. Its totient is φ = 76560984.

The previous prime is 121221671. The next prime is 121221733. The reversal of 121221729 is 927122121.

121221729 = 207² + 208² + ... + 719².

It is not a de Polignac number, because 121221729 - 2⁸ = 121221473 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121221739) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 354279 + ... + 354620.

It is an arithmetic number, because the mean of its divisors is an integer number (15359500).

Almost surely, 2^121221729 is an apocalyptic number.

121221729 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

121221729 is a deficient number, since it is larger than the sum of its proper divisors (63092271).

121221729 is a wasteful number, since it uses less digits than its factorization.

121221729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708924 (or 708921 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 121221729 is about 11010.0739779531. The cubic root of 121221729 is about 494.9106787103.

The spelling of 121221729 in words is "one hundred twenty-one million, two hundred twenty-one thousand, seven hundred twenty-nine".