21221352 has 40 divisors (see below), whose sum is σ = 59441250. Its totient is φ = 7073568.

The previous prime is 21221339. The next prime is 21221353. The reversal of 21221352 is 25312212.

It can be written as a sum of positive squares in only one way, i.e., 19766916 + 1454436 = 4446^2 + 1206^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21221353) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 15727 + ... + 17022.

Almost surely, 2^21221352 is an apocalyptic number.

It is an amenable number.

21221352 is an abundant number, since it is smaller than the sum of its proper divisors (38219898).

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

21221352 is a wasteful number, since it uses less digits than its factorization.

21221352 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32767 (or 32754 counting only the distinct ones).

The product of its digits is 240, while the sum is 18.

The square root of 21221352 is about 4606.6638687883. The cubic root of 21221352 is about 276.8583861711.

Adding to 21221352 its reverse (25312212), we get a palindrome (46533564).

The spelling of 21221352 in words is "twenty-one million, two hundred twenty-one thousand, three hundred fifty-two".