121383821 has 16 divisors (see below), whose sum is σ = 138544560. Its totient is φ = 105530880.

The previous prime is 121383793. The next prime is 121383863. The reversal of 121383821 is 128383121.

It can be written as a sum of positive squares in 8 ways, for example, as 60762025 + 60621796 = 7795^2 + 7786^2 .

It is a de Polignac number, because none of the positive numbers 2^k-121383821 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121386821) 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, 11531 + ... + 19383.

It is an arithmetic number, because the mean of its divisors is an integer number (8659035).

Almost surely, 2^121383821 is an apocalyptic number.

It is an amenable number.

121383821 is a deficient number, since it is larger than the sum of its proper divisors (17160739).

121383821 is a wasteful number, since it uses less digits than its factorization.

121383821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7936.

The product of its digits is 2304, while the sum is 29.

The square root of 121383821 is about 11017.4325956640. The cubic root of 121383821 is about 495.1311708970.

The spelling of 121383821 in words is "one hundred twenty-one million, three hundred eighty-three thousand, eight hundred twenty-one".