21023252 has 12 divisors (see below), whose sum is σ = 37785300. Its totient is φ = 10227456.

The previous prime is 21023213. The next prime is 21023257. The reversal of 21023252 is 25232012.

It can be written as a sum of positive squares in 2 ways, for example, as 7214596 + 13808656 = 2686^2 + 3716^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21023252.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21023257) 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, 70877 + ... + 71172.

It is an arithmetic number, because the mean of its divisors is an integer number (3148775).

Almost surely, 2^21023252 is an apocalyptic number.

It is an amenable number.

21023252 is a deficient number, since it is larger than the sum of its proper divisors (16762048).

21023252 is a wasteful number, since it uses less digits than its factorization.

21023252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142090 (or 142088 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 17.

The square root of 21023252 is about 4585.1119942702. Note that the first 3 decimals coincide. The cubic root of 21023252 is about 275.9942062776.

Adding to 21023252 its reverse (25232012), we get a palindrome (46255264).

The spelling of 21023252 in words is "twenty-one million, twenty-three thousand, two hundred fifty-two".