21431354 has 64 divisors (see below), whose sum is σ = 42024960. Its totient is φ = 7983360.

The previous prime is 21431353. The next prime is 21431359. The reversal of 21431354 is 45313412.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is not an unprimeable number, because it can be changed into a prime (21431353) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 189602 + ... + 189714.

It is an arithmetic number, because the mean of its divisors is an integer number (656640).

Almost surely, 2^21431354 is an apocalyptic number.

21431354 is a deficient number, since it is larger than the sum of its proper divisors (20593606).

21431354 is a wasteful number, since it uses less digits than its factorization.

21431354 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195.

The product of its digits is 1440, while the sum is 23.

The square root of 21431354 is about 4629.4010411715. The cubic root of 21431354 is about 277.7686341642.

Adding to 21431354 its reverse (45313412), we get a palindrome (66744766).

The spelling of 21431354 in words is "twenty-one million, four hundred thirty-one thousand, three hundred fifty-four".