21331370 has 8 divisors (see below), whose sum is σ = 38396484. Its totient is φ = 8532544.

The previous prime is 21331369. The next prime is 21331399. The reversal of 21331370 is 7313312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19864849 + 1466521 = 4457^2 + 1211^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1066559 + ... + 1066578.

Almost surely, 2^21331370 is an apocalyptic number.

21331370 is a deficient number, since it is larger than the sum of its proper divisors (17065114).

21331370 is a wasteful number, since it uses less digits than its factorization.

21331370 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2133144.

The product of its (nonzero) digits is 378, while the sum is 20.

The square root of 21331370 is about 4618.5896115589. The cubic root of 21331370 is about 277.3360013586.

Adding to 21331370 its reverse (7313312), we get a palindrome (28644682).

The spelling of 21331370 in words is "twenty-one million, three hundred thirty-one thousand, three hundred seventy".