84105621 has 20 divisors (see below), whose sum is σ = 127776000. Its totient is φ = 55116936.

The previous prime is 84105617. The next prime is 84105631. The reversal of 84105621 is 12650148.

It is not a de Polignac number, because 84105621 - 2² = 84105617 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84105601) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4021 + ... + 13578.

It is an arithmetic number, because the mean of its divisors is an integer number (6388800).

Almost surely, 2^84105621 is an apocalyptic number.

84105621 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

84105621 is a deficient number, since it is larger than the sum of its proper divisors (43670379).

84105621 is a wasteful number, since it uses less digits than its factorization.

84105621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17670 (or 17661 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 84105621 is about 9170.9116776905. The cubic root of 84105621 is about 438.1353963100.

Adding to 84105621 its reverse (12650148), we get a palindrome (96755769).

The spelling of 84105621 in words is "eighty-four million, one hundred five thousand, six hundred twenty-one".