23021621 has 24 divisors (see below), whose sum is σ = 29364120. Its totient is φ = 17912832.

The previous prime is 23021567. The next prime is 23021639. The reversal of 23021621 is 12612032.

It can be written as a sum of positive squares in 4 ways, for example, as 5499025 + 17522596 = 2345^2 + 4186^2 .

It is not a de Polignac number, because 23021621 - 2¹⁴ = 23005237 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 23021621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23024621) 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 23 ways as a sum of consecutive naturals, for example, 23681 + ... + 24633.

It is an arithmetic number, because the mean of its divisors is an integer number (1223505).

Almost surely, 2^23021621 is an apocalyptic number.

It is an amenable number.

23021621 is a deficient number, since it is larger than the sum of its proper divisors (6342499).

23021621 is a wasteful number, since it uses less digits than its factorization.

23021621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1013 (or 1006 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 23021621 is about 4798.0851388861. The cubic root of 23021621 is about 284.4757820303.

Adding to 23021621 its reverse (12612032), we get a palindrome (35633653).

The spelling of 23021621 in words is "twenty-three million, twenty-one thousand, six hundred twenty-one".