12720921 has 8 divisors (see below), whose sum is σ = 16981440. Its totient is φ = 8470512.

The previous prime is 12720889. The next prime is 12720941. The reversal of 12720921 is 12902721.

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

It is not a de Polignac number, because 12720921 - 2⁵ = 12720889 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12720891 and 12720900.

It is not an unprimeable number, because it can be changed into a prime (12720941) 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, 1195 + ... + 5183.

It is an arithmetic number, because the mean of its divisors is an integer number (2122680).

Almost surely, 2^12720921 is an apocalyptic number.

It is an amenable number.

12720921 is a deficient number, since it is larger than the sum of its proper divisors (4260519).

12720921 is a wasteful number, since it uses less digits than its factorization.

12720921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5055.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 12720921 is about 3566.6400154768. The cubic root of 12720921 is about 233.4386977658.

The spelling of 12720921 in words is "twelve million, seven hundred twenty thousand, nine hundred twenty-one".