21431136 has 24 divisors (see below), whose sum is σ = 56256984. Its totient is φ = 7143680.

The previous prime is 21431131. The next prime is 21431141. The reversal of 21431136 is 63113412.

It is an interprime number because it is at equal distance from previous prime (21431131) and next prime (21431141).

It is a tau number, because it is divible by the number of its divisors (24).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21431131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111525 + ... + 111716.

It is an arithmetic number, because the mean of its divisors is an integer number (2344041).

Almost surely, 2^21431136 is an apocalyptic number.

It is an amenable number.

21431136 is an abundant number, since it is smaller than the sum of its proper divisors (34825848).

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

21431136 is a wasteful number, since it uses less digits than its factorization.

21431136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223254 (or 223246 counting only the distinct ones).

The product of its digits is 432, while the sum is 21.

The square root of 21431136 is about 4629.3774959491. The cubic root of 21431136 is about 277.7676923390.

Adding to 21431136 its reverse (63113412), we get a palindrome (84544548).

The spelling of 21431136 in words is "twenty-one million, four hundred thirty-one thousand, one hundred thirty-six".