121807821 has 8 divisors (see below), whose sum is σ = 162498240. Its totient is φ = 81161312.

The previous prime is 121807817. The next prime is 121807823. The reversal of 121807821 is 128708121.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 121807821 - 2² = 121807817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121807823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3840 + ... + 16073.

It is an arithmetic number, because the mean of its divisors is an integer number (20312280).

Almost surely, 2^121807821 is an apocalyptic number.

It is an amenable number.

121807821 is a deficient number, since it is larger than the sum of its proper divisors (40690419).

121807821 is a wasteful number, since it uses less digits than its factorization.

121807821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21955.

The product of its (nonzero) digits is 1792, while the sum is 30.

The square root of 121807821 is about 11036.6580539582. The cubic root of 121807821 is about 495.7070072518.

The spelling of 121807821 in words is "one hundred twenty-one million, eight hundred seven thousand, eight hundred twenty-one".