10421721 has 6 divisors (see below), whose sum is σ = 15053610. Its totient is φ = 6947808.

The previous prime is 10421713. The next prime is 10421779. The reversal of 10421721 is 12712401.

10421721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 10017225 + 404496 = 3165^2 + 636^2 .

It is not a de Polignac number, because 10421721 - 2³ = 10421713 is a prime.

It is a super-2 number, since 2×10421721² = 217224537203682, which contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 10421694 and 10421703.

It is not an unprimeable number, because it can be changed into a prime (10421711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 578976 + ... + 578993.

It is an arithmetic number, because the mean of its divisors is an integer number (2508935).

Almost surely, 2^10421721 is an apocalyptic number.

It is an amenable number.

10421721 is a deficient number, since it is larger than the sum of its proper divisors (4631889).

10421721 is a wasteful number, since it uses less digits than its factorization.

10421721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1157975 (or 1157972 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 18.

The square root of 10421721 is about 3228.2690408329. The cubic root of 10421721 is about 218.4304334074.

The spelling of 10421721 in words is "ten million, four hundred twenty-one thousand, seven hundred twenty-one".