8407921 has 8 divisors (see below), whose sum is σ = 8591400. Its totient is φ = 8226432.

The previous prime is 8407909. The next prime is 8407943. The reversal of 8407921 is 1297048.

It can be written as a sum of positive squares in 4 ways, for example, as 26896 + 8381025 = 164^2 + 2895^2 .

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 8407921 - 2⁹ = 8407409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8407951) 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, 10491 + ... + 11263.

It is an arithmetic number, because the mean of its divisors is an integer number (1073925).

Almost surely, 2^8407921 is an apocalyptic number.

It is an amenable number.

8407921 is a deficient number, since it is larger than the sum of its proper divisors (183479).

8407921 is a wasteful number, since it uses less digits than its factorization.

8407921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 8407921 is about 2899.6415295688. The cubic root of 8407921 is about 203.3431471270.

It can be divided in two parts, 84079 and 21, that added together give a square (84100 = 290²).

The spelling of 8407921 in words is "eight million, four hundred seven thousand, nine hundred twenty-one".