8391621 has 8 divisors (see below), whose sum is σ = 12787264. Its totient is φ = 4795200.

The previous prime is 8391589. The next prime is 8391623. The reversal of 8391621 is 1261938.

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

It is not a de Polignac number, because 8391621 - 2⁵ = 8391589 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8391623) 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, 199780 + ... + 199821.

It is an arithmetic number, because the mean of its divisors is an integer number (1598408).

Almost surely, 2^8391621 is an apocalyptic number.

It is an amenable number.

8391621 is a deficient number, since it is larger than the sum of its proper divisors (4395643).

8391621 is a wasteful number, since it uses less digits than its factorization.

8391621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 399611.

The product of its digits is 2592, while the sum is 30.

The square root of 8391621 is about 2896.8294737523. The cubic root of 8391621 is about 203.2116585190.

The spelling of 8391621 in words is "eight million, three hundred ninety-one thousand, six hundred twenty-one".