21144357 has 24 divisors (see below), whose sum is σ = 33173504. Its totient is φ = 12900384.

The previous prime is 21144341. The next prime is 21144373. The reversal of 21144357 is 75344112.

21144357 is a `hidden beast` number, since 211 + 443 + 5 + 7 = 666.

It is an interprime number because it is at equal distance from previous prime (21144341) and next prime (21144373).

It is not a de Polignac number, because 21144357 - 2⁴ = 21144341 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21144357.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144307) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14148 + ... + 15570.

Almost surely, 2^21144357 is an apocalyptic number.

It is an amenable number.

21144357 is a deficient number, since it is larger than the sum of its proper divisors (12029147).

21144357 is a wasteful number, since it uses less digits than its factorization.

21144357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1569 (or 1566 counting only the distinct ones).

The product of its digits is 3360, while the sum is 27.

The square root of 21144357 is about 4598.2993595459. The cubic root of 21144357 is about 276.5231492226.

Adding to 21144357 its reverse (75344112), we get a palindrome (96488469).

The spelling of 21144357 in words is "twenty-one million, one hundred forty-four thousand, three hundred fifty-seven".