8421645 has 16 divisors (see below), whose sum is σ = 13660992. Its totient is φ = 4429440.

The previous prime is 8421641. The next prime is 8421653. The reversal of 8421645 is 5461248.

8421645 = 303² + 304² + ... + 375².

It is not a de Polignac number, because 8421645 - 2² = 8421641 is a prime.

It is a super-3 number, since 3×8421645³ (a number of 22 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8421641) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2751 + ... + 4940.

It is an arithmetic number, because the mean of its divisors is an integer number (853812).

Almost surely, 2^8421645 is an apocalyptic number.

It is an amenable number.

8421645 is a deficient number, since it is larger than the sum of its proper divisors (5239347).

8421645 is a wasteful number, since it uses less digits than its factorization.

8421645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7772.

The product of its digits is 7680, while the sum is 30.

The square root of 8421645 is about 2902.0070640851. The cubic root of 8421645 is about 203.4537239805.

The spelling of 8421645 in words is "eight million, four hundred twenty-one thousand, six hundred forty-five".