21323646 has 24 divisors (see below), whose sum is σ = 46441200. Its totient is φ = 7070976.

The previous prime is 21323641. The next prime is 21323647. The reversal of 21323646 is 64632312.

21323646 is a `hidden beast` number, since 2 + 13 + 2 + 3 + 646 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323641) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 606 + ... + 6558.

It is an arithmetic number, because the mean of its divisors is an integer number (1935050).

Almost surely, 2^21323646 is an apocalyptic number.

21323646 is an abundant number, since it is smaller than the sum of its proper divisors (25117554).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21323646 is a wasteful number, since it uses less digits than its factorization.

21323646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6160 (or 6157 counting only the distinct ones).

The product of its digits is 5184, while the sum is 27.

The square root of 21323646 is about 4617.7533498445. The cubic root of 21323646 is about 277.3025232482.

Adding to 21323646 its reverse (64632312), we get a palindrome (85955958).

It can be divided in two parts, 2132 and 3646, that added together give a triangular number (5778 = T₁₀₇).

The spelling of 21323646 in words is "twenty-one million, three hundred twenty-three thousand, six hundred forty-six".