21331460 has 24 divisors (see below), whose sum is σ = 45467520. Its totient is φ = 8404704.

The previous prime is 21331459. The next prime is 21331469. The reversal of 21331460 is 6413312.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (21331469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6620 + ... + 9299.

It is an arithmetic number, because the mean of its divisors is an integer number (1894480).

Almost surely, 2^21331460 is an apocalyptic number.

21331460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21331460 is an abundant number, since it is smaller than the sum of its proper divisors (24136060).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21331460 is a wasteful number, since it uses less digits than its factorization.

21331460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15995 (or 15993 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 21331460 is about 4618.5993547828. The cubic root of 21331460 is about 277.3363913977.

Adding to 21331460 its reverse (6413312), we get a palindrome (27744772).

The spelling of 21331460 in words is "twenty-one million, three hundred thirty-one thousand, four hundred sixty".