121728231 has 16 divisors (see below), whose sum is σ = 189830400. Its totient is φ = 76880664.

The previous prime is 121728209. The next prime is 121728239. The reversal of 121728231 is 132827121.

It is not a de Polignac number, because 121728231 - 2²³ = 113339623 is a prime.

It is a super-2 number, since 2×121728231² = 29635524444778722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 121728195 and 121728204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121728239) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 118131 + ... + 119156.

It is an arithmetic number, because the mean of its divisors is an integer number (11864400).

Almost surely, 2^121728231 is an apocalyptic number.

121728231 is a deficient number, since it is larger than the sum of its proper divisors (68102169).

121728231 is a wasteful number, since it uses less digits than its factorization.

121728231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237315 (or 237309 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 121728231 is about 11033.0517537080. The cubic root of 121728231 is about 495.5990176976.

The spelling of 121728231 in words is "one hundred twenty-one million, seven hundred twenty-eight thousand, two hundred thirty-one".