2173621 has 4 divisors (see below), whose sum is σ = 2195244. Its totient is φ = 2152000.

The previous prime is 2173601. The next prime is 2173643. The reversal of 2173621 is 1263712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1703025 + 470596 = 1305^2 + 686^2 .

It is a cyclic number.

It is not a de Polignac number, because 2173621 - 2¹⁷ = 2042549 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2173592 and 2173601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2173601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10660 + ... + 10861.

It is an arithmetic number, because the mean of its divisors is an integer number (548811).

2^2173621 is an apocalyptic number.

It is an amenable number.

2173621 is a deficient number, since it is larger than the sum of its proper divisors (21623).

2173621 is a wasteful number, since it uses less digits than its factorization.

2173621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21622.

The product of its digits is 504, while the sum is 22.

The square root of 2173621 is about 1474.3205214606. The cubic root of 2173621 is about 129.5372303424.

Subtracting from 2173621 its reverse (1263712), we obtain a palindrome (909909).

The spelling of 2173621 in words is "two million, one hundred seventy-three thousand, six hundred twenty-one".