21331357 has 16 divisors (see below), whose sum is σ = 23284800. Its totient is φ = 19474560.

The previous prime is 21331339. The next prime is 21331361. The reversal of 21331357 is 75313312.

It is a cyclic number.

It is not a de Polignac number, because 21331357 - 2¹⁹ = 20807069 is a prime.

It is a super-2 number, since 2×21331357² = 910053582922898, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331157) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 108183 + ... + 108379.

It is an arithmetic number, because the mean of its divisors is an integer number (1455300).

Almost surely, 2^21331357 is an apocalyptic number.

It is an amenable number.

21331357 is a deficient number, since it is larger than the sum of its proper divisors (1953443).

21331357 is a wasteful number, since it uses less digits than its factorization.

21331357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396.

The product of its digits is 1890, while the sum is 25.

The square root of 21331357 is about 4618.5882042027. The cubic root of 21331357 is about 277.3359450195.

Adding to 21331357 its reverse (75313312), we get a palindrome (96644669).

It can be divided in two parts, 21331 and 357, that multiplied together give a palindrome (7615167).

The spelling of 21331357 in words is "twenty-one million, three hundred thirty-one thousand, three hundred fifty-seven".