21252141 has 6 divisors (see below), whose sum is σ = 30697550. Its totient is φ = 14168088.

The previous prime is 21252139. The next prime is 21252149. The reversal of 21252141 is 14125212.

It can be written as a sum of positive squares in only one way, i.e., 21068100 + 184041 = 4590^2 + 429^2 .

It is not a de Polignac number, because 21252141 - 2¹ = 21252139 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252149) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1180666 + ... + 1180683.

Almost surely, 2^21252141 is an apocalyptic number.

It is an amenable number.

21252141 is a deficient number, since it is larger than the sum of its proper divisors (9445409).

21252141 is a wasteful number, since it uses less digits than its factorization.

21252141 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2361355 (or 2361352 counting only the distinct ones).

The product of its digits is 160, while the sum is 18.

The square root of 21252141 is about 4610.0044468525. The cubic root of 21252141 is about 276.9922148064.

Adding to 21252141 its reverse (14125212), we get a palindrome (35377353).

The spelling of 21252141 in words is "twenty-one million, two hundred fifty-two thousand, one hundred forty-one".